Tutorials/Traps

This is a list of traps for creatures or players. Add your own, if you have created and tested a different one. Traps are a subset of Mechanisms.

Wired Traps
Wired traps are traps using Redstone circuits to damage/kill/trap the victim. Note that many TNT traps have the disadvantage of destroying the area around them, making the player have to rebuild it every time. Using water or obsidian will nullify the damage


 * Arrow Dispenser Trap
 * Probably one of the simplest and most obvious traps, but also one of the weakest. Simply point a dispenser at a pressure plate, fill the dispenser with arrows, and wire the pressure plate to the dispenser. Anything that steps on the pressure plate gets hit with an arrow. Unfortunately, this trap only does minimal damage, and isn't likely to kill anything unless you place the pressure plate in such a way that the enemy would be hit into an alcove each time they step on it, thus trapping them until they are killed. In addition, the dispenser always needs to have a supply of arrows in order for the trap to function. By adding a Pulse Generator you can make a more effective arrow dispenser trap that doesn't require constant activating.


 * Advanced Arrow Dispenser


 * Created by attaching an Arrow Dispenser to a Clock Generator. The constantly toggling output of the Clock Generator will allow the Dispenser to fire continuously until it is out of arrows.  The 'fire-rate' of the trap can be increased by attaching the Dispenser to multiple redstone torches in the clock or using a more rapid clock design.  By connecting one of the redstone torches to a lever it is possible to turn the Trap on and off.

Another way of doing this for a much higher fire rate (pretty much maximum) is to wire two separate inputs to each dispenser (like one above and to the left and the other below). One input should be wired to a pulse generator, the other to something like a pressure plate, switch, or button. When the switch is on, the dispenser should rapid fire. When it is off, nothing should fire at all, even though the pulse generator is still on. Video Tutorial http://www.youtube.com/watch?v=kIXIoocBa3k

-The Trap can be automated by using a pressure plate to manipulate a water current to sever the connection between the Clock and the On/Off lever. A simple Video showing an automatic arrow dispenser in a trap : http://www.youtube.com/watch?v=0NhBbNsTm0k
 * Hidden Arrow Dispenser
 * This is very similar to the Arrow Dispenser trap, but harder to detect. Dig a hole in the wall two blocks deep, place a Dispenser filled with arrows in the hole, cover it up, and wire it to a pressure plate, or even better, a switch also wired to an iron door. When a player or mob steps on the pressure plate, an arrow shoots out of the wall and pegs them in the side.. This works excellently against thieving players invading your base, and is even better if at the opposite side of the dispenser, there is a deep pit, or one filled with lava, and there is just a one block wide walkway. Then invite your enemies over.

NOTE: This will only work if the dispenser faces west or south, north being the direction the clouds travel in.


 * Snowball pitfall trap
 * Load the dispenser with snowballs or eggs, whichever you find easier to get, and aim the dispenser at a connected pressure plate by a hole. If something walks across the plate, the dispenser shoots an egg or snowball to knock the intruder into the pit, where they can be dealt with however you like.  Eggs and snowballs work equally well, though eggs are more amusing due to the chickens that crowd the pit. However, it is considerably more difficult to get that many eggs.


 * Simple arrow Dispenser trap
 * Not the hardest of traps to make, but is made by putting arrow dispenser at the bottom of a hole and having a lever activate a clock generator which will fire the arrows against mobs that have fallen into the hole. The trap is not practical because you would need to add arrows into the dispenser every time you run out, which means you would need to constantly "maintain" the trap.

A video showing the Simple arrow dispenser trap in a hole : http://www.youtube.com/watch?v=8wB67vMHU0A


 * Wired TNT
 * Wired TNT is a basic example of a wired trap. It is created by placing a TNT block below the floor or in the wall and wiring it to a pressure plate. Often the TNT is spaced from the plate so when the victim activates the explosive the TNT has time to cook before the victim is right above/beside it. A very common form of this trap is a TNT landmine with bait to lure thieves in. Iron Ore or Gold Ore are good things to use because the TNT will be done cooking by the time they break the ore off the wall.


 * One Way Door
 * A one way door is made by placing a pressure plate in front of a iron door to a closed room with no way to open the door from the inside. Anything can enter, but once the door shuts the mob will remain trapped. This technique is useful for capturing mobs for resource harvesting.


 * Inescapable Door Room
 * This trap consists of four doors surrounding a pressure plate, so that the doors are open naturally and closed when the pressure plate is activated. Place the doors with the doorknob towards the pressure plate to achieve this. Anything that then steps on the pressure plate will be trapped. It is however possible for mobs to escape by jumping up and down, so to make this trap effective it is important to include a roof. This trap can be expanded to cover a large area by making a ring of doors surrounding a ring of pressure plates, any mob that attempts to leave the enclosed area will have a door slam in their face. Note that this trap does not work on other players unless iron doors are used.


 * Roof TNT Trap
 * A roof TNT trap can be created by putting a pressure plate below a TNT (in the ceiling) then wiring (with Redstone) the pressure plate to the TNT so when someone or something triggers the pressure plate, the TNT will fall in front of them and explode. Note that this trap works best on mobs because they are not alarmed at the sight of TNT falling right in front of them. Placing TNT in such a way that the player is surrounded will not help because players can walk through activated TNT because activated TNT is a non-repelling entity.


 * One Way Door to Roof TNT Trap
 * The One Way Door to Roof TNT Trap can be made by using the One Way Door technique entering into a 1x2 hallway of any length, putting a pressure plate two blocks after the door and then making a Roof TNT Trap. With this mechanism completed, everyone who goes through the door will have to step onto the pressure plate, causing the TNT to fall and kill them. You can even wire a new steel door at the end of the hallway, that starts open, so the victim thinks they see a way out, but that closes after you step on the TNT pressure plate, making this trap a powerful and inescapable one.
 * This trap can also be wired off to a single pressure plate (outside the door) with some intelligent wiring.


 * Decoy TNT House
 * Made by building the frame of a house of any size out of TNT, minus roof, and with a three space wide opening (this is extremely expensive, and you can not make any mistakes), then covering it with stone or another material, except for two blocks connecting the TNT at the entrance. Make the floor out of solid stone and wire to the two holes. Connect a stone pressure plate to the Redstone, and have an empty chest in the decoy house to attract thieves. When the player walks in they step on the pressure plate, triggering the TNT lined in the walls. This trap is more for effect than utility, since it's so expensive and cannot be salvaged.


 * Wired TNT Pitfall
 * Create a deep 3x3 pit (deep enough so mobs will die upon hitting the bottom). Two blocks down from the surface, place a layer of stone or cobblestone. On top of that, do the same, but make sure the center block is TNT. Finally, place a layer of any block type on top (except TNT, of course). An advantage to stone/cobblestone is that it takes less blocks, while an advantage to dirt is that upon the TNT's explosion, it creates a small ledge around the pit you can stand on to help rebuilding. After your top layer is done, put a pressure plate on the block above the TNT. When a mob - or player - walks on the plate, the TNT will go off, damaging them and making them fall to their death in the pit below.


 * You might want to try creating a hallway or corridor of some sort that links the bottom of the pit to your base so that you can pick up any items dropped by mobs afterward, along with the blocks left behind.


 * Wired Self-Destruct
 * Place blocks of TNT, with 1-2 blocks in-between them, behind your walls. Place the switch in a secret location outside of your base, that only you know. This is to prevent you from killing yourself, and also to prevent other people for destroying your base.


 * Wired Water/lava Pitfalls
 * Using redstone circuits to control the flow of water/lava, you can make Pitfall by causing the water/lava to run into (preferably) a corridor of torches which hold up sand. This will cause the victim to either drown if water, or burn if lava. Lava example---updated version


 * Wired Minefield
 * Using redstone and usually a large amount a TNT, you can set off a field of TNT, which can kill multiple mobs, unlike most other traps. This can also be done with a pressure plate, but will be more than necessary to kill a single mob. This can also be done in multiplayer, but it would be wise to bury the TNT so that unsuspecting player(s) will not be able to disarm it, or avoid the field.

Make a large bridge, atleast 25 blocks long, out of stone or cobblestone. Make a platform of Obsidion about 18 blocks away from the start of the bridge, and place six blocks of TNT on it. Create a fake hill, and have the inside hollowed out to place redstone going from two switches at the begining of the bridge, to the TNT, the first TNT will break the bridge, and the rest will kill them, the Obsidion will resist the explosion, so you don't have to mine more. You may also want to make somthing to atract theives, "Monster Trap" "Property of [name] DO NOT TOUCH]" "WARNING! EXPLODING BRIDGE" the last of which is to make people think you're lying about there being any trap.
 * Exploding Bridge

Other explosive traps

 * Explosive Arrow
 * This trap consists of a TNT Box covered in arrows, then set off to pepper the surrounding landscape with deadly projectiles. Video example. Also can be combined with the Redstone Dust "wires" for remote detonation.


 * Land mines
 * These simple traps are useful (but expensive) for killing mobs and players.


 * Randomly dig holes that are three blocks deep and place a block of TNT in the top of the hole. Place a stone pressure plate on top of the TNT, or a wooden one if you're cheap or expect people to throw blocks around (wood plates are set off by thrown items). When an unfortunate player or mob stands on the TNT, they will be trapped in the hole and killed by the TNT under their feet. Video tutorial here


 * A simpler type of landmine trap is made by digging 1 block out, placing a TNT in the hole, then placing a pressure plate on top of it, so when a mob walks above of it, they might get blown up. This is less effective since the TNT has a five-second delay before it detonates.


 * This can also be accomplished by digging a hole four blocks deep, and putting one block of TNT in the hole, one space away from the top (with two empty spaces beneath it, if your hole is four blocks deep), placing a sand block on top of the TNT (to hide the TNT), and a pressure plate on top of the sand. If it's stepped on, the TNT will activate and fall. The sand will fall too, as it was being held up by the TNT, and the player will fall with the sand, and be trapped in a hole with active TNT.


 * Note: The pressure plate may be destroyed in the explosion.


 * Another way to do this, but without creating a massive hole, is to place a single block of water at the bottom of a pit. You can dig the pit however deep you want, put a single TNT block one block down from the top of the pit, and place a pressure plate on the TNT block. When a player or mob lands on the pressure plate, it will activate the TNT and drop both the player and TNT into the water at the bottom. The water prevents the TNT from blowing up a hole, but it still should damage the mob or player enough to kill it. Another way is to dig a hole 2 blocks deep, with a one block side extension into the wall. Place water in this extension, and at the very top of the hole, put TNT, covered by a pressure plate. When a mob steps on it, they fall down into the hole and cannot jump out. Because of the water, when the TNT explodes, it will do no landscape damage, yet it will still kill.


 * Animal Trap
 * This trap lures animals into it, and then kills them. You need 1-5 torches, 13 redstone (at least), 16 stone pressure plates (at least), and 1 TNT.


 * Place your pressure plates in a 5x5 square (at least), and then outline the inside with your redstone. Then, make a direct line from one of the redstone to the TNT with redstone, make sure you're not going diagonal. Then, place 1 torch on each corner of the TNT then if you got 5 torches, place 2 blocks above the TNT and put a torch on that block. Then delete the block under it and place your last redstone on the TNT. Then make a run for it.


 * Useful for killing those pesky cows and pigs.


 * Inescapable path(For other players)
 * You will need
 * - 1 block of Soul Sand
 * - 2 stone Pressure Plate
 * - 1 block of TNT
 * - 20 blocks of Cobblestone
 * - Something to lure the other player through


 * Method:
 * _=Ground
 * -Using the Cobblestone, make a shape like this:
 * -Using the Cobblestone, make a shape like this:

C C CCC CCC C C Underground
 * -Skip a space adjacent to it and copy the shape.
 * You should now be able to walk in between the structure.
 * -Now take your last two Cobblestone blocks and put them in between the pillars that are three blocks high(Not the part in the middle.). Looking through the structure it should look like this:
 * -Now take your last two Cobblestone blocks and put them in between the pillars that are three blocks high(Not the part in the middle.). Looking through the structure it should look like this:

CCC C C C_C C Underground
 * -Take your Soul Sand and place it like this:
 * Looking at the side

C C CCC CCC CSC Underground
 * Looking through
 * Looking through

CCC C C C C   S  Underground
 * -Now place your TNT blocks like this:
 * Looking from the side
 * Looking from the side

C C CCC CCC CSCT Underground
 * -Place your Pressure Plates on the blocks of Cobblestone that are in the ground so regardless pf which way the other player goes through they will set off the TNT block.
 * -Finally, place Lure(s) in a way so the victim will go over the soul sand. This can be achieved by placing gems going through the structure, or one item of value over the block of Soul Sand.
 * -Finally, place Lure(s) in a way so the victim will go over the soul sand. This can be achieved by placing gems going through the structure, or one item of value over the block of Soul Sand.
 * -Finally, place Lure(s) in a way so the victim will go over the soul sand. This can be achieved by placing gems going through the structure, or one item of value over the block of Soul Sand.


 * Explanation:
 * From the Soul Sand page:


 * "When placed on the ground in front of a two-block high ceiling, soul sand prevents players from going through it from the front, making it useful for making one-way passages or invisible barriers. This affects mobs too as they have to jump to get out of the slowing effects of the block and thus unable to get through the door."


 * The player will get stuck in the Soul Sand when they go over it. However, this trap does not work if the roof is complete hence the reason you use 20 Cobblestone blocks instead of 21.

Pitfall
This trap has several variants:


 * Simple pit
 * The walls are two blocks or more tall to prevent mobs from escaping. To trap spiders, the hole must be at least two spaces wide and three spaces tall (As of Beta 1.2 spiders can climb walls, so now to trap spiders the base of the pitfall must be wider than the top, so they hit a ceiling when they try to climb out).


 * Deep pit
 * Kills victims with falling damage (dangerous to the player).


 * Lava pit
 * Lava at bottom kills victims quickly at the cost of losing the loot gained from the victim.


 * Fire pit
 * A pit three blocks deep lined at the bottom with Logs or Netherrack, which are then ignited with a Flint and Steel. Some may need to be replaced if they burn away (If you use Netherrack it will burn forever), but eventually they should reach a state of permanent burn. It should be noted that loot will also be lost in the fire. If you only use one source of fire for every 5x5 block area, you increase the chances of the loot not being destroyed.


 * Shallow Pit
 * A 1-block deep pit with fences lining the inner edge. Since fences count as one and one half blocks high for mobs, they can easily walk in, but cannot jump out.
 * Doesn't trap spiders, as they can jump two blocks high, as well as climb walls.


 * Player-triggered Sand-hatch pit
 * A sand floor held up by torches falls when a player removes a block or torch. Can be activated by lever using redstone to control water flow.Video Example


 * Pitfall TNT
 * Used in conjunction with a Simple or Deep pit. Place a TNT at the beginning of the hole, and with the use of an adjacent wall to the hole, place a pressure plate on top of the TNT (Attempting to place the plate on the TNT itself will only trigger the TNT. Anything stepping on the plate will trigger the TNT, causing it to fall and destroy the plate, but it also causes whatever stepped on it to fall down the pit with it, trapping it with a lit box of explosives.


 * The Road of Doom
 * An expensive, but extremely effective trap. Make any length and width of a "gravel road". Below the level gravel, place a level of TNT (so for an example for a 4 block long doomroad you need a 1x4x4 area). Wire the TNT with redstone to a button or switch on your side. When another player steps on your road, you can just fire up the TNT and watch as the player hopelessly falls into a pit of TNT. Be sure to wear safety goggles. If you expect an army at your front door, give them a nice long and wide gravel road to march to your base on. Then steal the ground below them.


 * Cactus trap
 * Essentially a normal pitfall trap, which has a floor of cacti, causing any creature (or player) damage as they step on it.
 * Note: Cacti cannot be placed next to other blocks anymore, making this harder to pull off. However, the staggered placement of cacti can create an effective "kill wall" that can be placed around or at strategic points in your base. In roughly 1-2 days the wall will reach maximum height and creatures will no longer be able to jump over the cacti continuously injuring themselves.


 * The Surprise Death
 * This trap is an efficient way to slowly destroy enemy mobs, but only mobs, and possibly not spiders. Create a long hallway, with a height of 3 squares. Fill the walls at the bottom level(at 'foot' level of player) with reeds, and hollow out walls around to accommodate the reeds. As reeds create a 1x1x1 air pocket around themselves, this should guarantee air at the level of the players head. Ladders may be used as well, as they have the same effect without needing water. Now flood the top of the hall (3 squares from ground) with water. You can now build a hole halfway down the hall, approx 3 squares long. To escape the trap simply float with your head in the water, while walking forward. If you can hold your breath for a long enough span(in ratio to the length of your hole) then you can simply drop on the far side. The hole could be extremely deep, filled with Cactus, or containing a Pitfall TNT trap. The possibilities are endless!


 * Pit around your house
 * This trap is essentially a hole. Enemies can only jump as high as you do, so a simple 1x1x2 (1 block area, 2 blocks deep) will capture any enemies who walk over it.

However, spiders can jump over pits as wide as two or three blocks and they can climb out. So be sure to dig out the blocks on the lowest level.
 * By strategically placing these pits at the entrances to your base, you can ensure entire areas are off-limits to monsters while retaining your ability to access them (via small jumping puzzles)
 * Video example with a way to deal with NPCs stuck in the trap.


 * Pit around your house 2.0
 * This trap builds on the idea of having a pit around your house by allowing you to also kill the mobs without any danger to yourself.
 * A second pit which only the player has access to is dug 1 block below the pit where the mobs fall. A 1x1 window can then be made where the player can hit the mob's feet and kill them.
 * Video tutorial


 * Pitfall 2.0
 * Dig a pit 3x3x3, then cover it with doors that close into the pit. Wire all the doors to a row of pressure plates, when they trip the pressure plate, the doors open, they walk forward and fall in. You may want to fill the pit with water or lava or add a fire in it. Water is best, it drowns them and you don't lose your drops. You can also connect the pressure plates to a memory switch that keeps a torch lit to tell you if a mob fell in.


 * Pitfall 3.0
 * Dig a deep, wide pit, around 4 blocks of depth and however long you want. Make a base in the middle, with holes around the bottom and an entrance at the top which you must jump for. Using this, you can lure mobs to follow you, jump up to your safe spot, and the mobs will fall below, allowing you to go to the bottom part of your base to kill them with ease. An example of this is shown here


 * Pit with Suspended Lava
 * Similar to a pit with lava at the bottom, but the lava is suspended by a non flammable block, allowing you to retrieve possible loot. Make a 2x2 pit, at least 4 blocks deep. At least 1 block down from the surface and 2 blocks above the bottom of the pit, mine 4 blocks from the walls of the pit to create holes of 1x2 or 1x1. Put something to support the lava underneath the area you just created, such as a ladder, a door (if the area is two blocks above the bottom of the pit), or even reed. Put lava in the holes. If you want, you can do the same process again one block away from the first pit before you put in the lava. This can create an effective string of traps.


 * Pit with Current Dragging into It
 * It is a useful trick with any pit to dig out a square 5*5*1 blocks at the top (works for a 2*2 pit) and place water springs in the corners, so that anything which lands in the water will be dragged into the pit and fall to its death.


 * Fire pit with Soul Sand.
 * It is quite a simple trap you can use for looting passive and hostile mobs (mostly passive). Dig a 2x2x2 pit and fill the bottom with Netherrack or Wood leaving one block of space left. Place a square of Soul Sand around the fire pit. The size of the square depends on how long you want to slow the mobs. The trap works like this: The mobs will walk into the fire pit causing themselves to burn. They then jump out of the pit and start wandering around. The soulsand slows them down so you don't have to wander all over the place to collect the loot.

Water traps

 * Drowning
 * This trap uses the removal of a block as a trigger to release sand doors, and open a water pipe, causing a room to become closed off and filled with water. The water can now be placed using buckets.
 * A problem with this trap is that the sand doors have to be either very tall, or very many, in order to prevent the player from simply digging his way out.
 * The use of sand wires instead of water channels would make the doors closing instantaneous.
 * Video example (slow, escape-able)


 * Retrieval Traps trap.jpg
 * Create a current by using a bucket that drags the mobs down into a water filled hole or some such, with blocks above their heads so they can't resurface. The mobs drown in this 'prison' and their loot sinks to the floor, where it can flow through a hole in the end wall and into your house/dwelling. You get all of the loot, with none of the effort of getting it! Video example.

A sunlight death chamber is simply a water current that deposits mobs in a room with a glass ceiling. Go to the trap after its daytime to collect your treasure. (note: this trap only works on zombies & skeletons)
 * Sunlight death chamber


 * Water Suction Traps
 * Use a bucket to remove a block under the spot in a lake or ocean you want mobs to be stuck (if they swim too close)
 * Note: Not very effective (only confirmed to work with sheep, pigs and cows)


 * Lava Retrieval Traps
 * Normally the use of lava in a trap, despite its indisputable effectiveness at killing, results in the loss of all items dropped. However, with some cleverness, this can be circumvented, producing an exceptionally fast-acting trap which allows you to recover all items.  Build a two or more wide instance of the following side view, in which "#" represents a normal block (I recommend glass, if possible, for maximum entertainment value), ">>WATER>>" represents water (leftmost is a source tile), "LAVA" represents lava (source tile on the right, opposite to the flow of the water), and "|" represents a sign or a ladder(or anything else which will prevent lava from flowing through a tile but allow mobs to pass):

LAVA# >>WATER>> |#####
 * 1) >>WATER>__<-- goodies go here :)
 * Note that lava runs out after three tiles, resulting in the final tile of lava being suspended in midair by the ladder.
 * Mobs falling in the top (fed there by a system of streams, for example) will be forced by the water current into the chest-high lava, which is suspended in midair by the ladder. This will rapidly kill them, but as there is only air and water beneath the single lava tile, the items spawned from their corpse will remain undamaged, and be swept to safety at the far right of the system.  This will even work effectively on spiders, thanks to their tendency to jump repeatedly in water—although you may find chickens have a tendency to slip through.
 * For best results, combine with a final perpendicular-flow water current on the far right to deliver all items to a single tile, on which a wooden pressure plate may be placed and attached to redstone torches to indicate the availability of items.

For a complete walkthrough on this method, watch this tutorial.

Minecart traps
Minecart traps are based on the principle that mobs both good and evil jump into minecarts passing by. An example of a Minecart trap can be found on Youtube.


 * Minecart bumping trap
 * This trap consist of a looping track powered by boosters and containing a low and slow section where any passengers will bump their head until they die.


 * Minecart drowning trap
 * Similar to the Minecart bumping trap, this method uses water to drown mobs. Note that minecarts will continue to travel through water and small holes regardless.


 * Minecart lava trap
 * This is a fast acting trap in which minecarts are ultimately destroyed by lava. Players who find themselves in this situation often have little or no time to react.

Other traps

 * Burning log trap
 * This trap consists only of a single log block that has been set on fire. It will attract cows, sheep, chickens,and pigs to it, and they will jump onto the log and be killed via their being caught on fire. The dropped items will be available, except for sheep, which will not give a drop. It must be made clear that this trap is only of middling effectiveness, but is an easy way to get leather, pork, and feathers. Interestingly enough, pigs can turn kamikaze when encountering this trap and have been known to set other pigs on fire. The player seems to be immune to this though.


 * Burning Netherrack/Cactus trap hellstone catai trap.png and Cacti.]]
 * A variant of the aforementioned trap. Mobs will be lit on fire, then hit the cactus and usually jump back, leaving the drops safe, and an effective barrier, especially against spiders. This requires a cactus farm, as it requires lots and lots of it to be effective.


 * Mob Tower trap


 * Although lengthy and very difficult to build, the payoff is fantastic. Construct a huge tower, which height depends on how much time you have on your hands, how many materials you have, and how many mob drops you want. The contraption drags mobs into a grinder and drops the loot into your base. To build the tower, watch this tutorial:


 * Cactus Wall trap


 * This trap is simple enough, the only difficulty being that you need a hefty amount of Cacti, an optimal choice would be to use Cactus Farming. It does work somewhat well as a trap and defense mechanism, killing most creatures, as the Cactus will hurt most mobs attempting to pass through, be they lured or independent. See the video as an example: http://www.youtube.com/user/Calobrin#p/c/EA3333670DAD5D8A/19/Omo_9r0w2cs


 * This is another video of a cactus wall. It shows how to use the wall to actively destroy monsters that are near your base without wasting arrows by "fishing for monsters". http://www.youtube.com/watch?v=2kpho89FiO8


 * Treasure Chest Lava trap
 * create a room of any size that is 3 blocks high in any spot place any non flammable block. Next destroy the ceiling block directly above it. Place a chest on top of the first block and then a block on top of the chest this is the trigger block (still non flammable). Go up on top of the roof of your room and fill the hole there with lava. Because you cannot open a chest that has a block above it players will destroy the block on top of the chest and release the lava burning them and the chest. To reset this trap simply scoop up the lava source block replace the chest and the trigger block and then replace the lava. It is very effective at keeping thieves out of your things in smp. Example here


 * "Toaster" Trap
 * A directionally-dependent trap, the east sides of blocks holding lava or consisting of burning netherracks will cause a half-heart damage to players or mobs on normal difficulty.  Likewise, the north-east corner of a single contained block of lava or burning material will do the same.  The so-called Toaster Trap relies on this peculiar phenomenon to use water and push the desired victims towards the west or south-west to trap them against the burning side but retain any items due to the fact that the fire/lava is covered and doesn't touch them directly.
 * Single block method: http://www.youtube.com/watch?v=9yaaolztCDQ
 * Row method: http://www.youtube.com/watch?v=bEnBUi7-3c4


 * Fire Pit trap
 * make a hole 2 blocks deep but doesnt matter how big. now fill the bottom with netherrack and take flint and steel and light each block.  mobs will fall into the hole, and burn and die.  the bigger the hole the more effective the trap will be.  the trap is very effective in killing anything that falls into it.


 * Lava ladder trap
 * This it a simple trap that is great for trapping and killing players on a SMP server.

Make a 'dummy house'(A house that isnt really a house, its only to lure people). Put some ladders that go to a second floor and at the top of the ladder put some lava, The lava wont go down the ladders. Now when people go up the ladder they will climb into the lava! and usually falling off the ladder so their items wont burn. This trap will also work downwards but it is not as effective.