Tutorials/Mob grinder

Mob grinders are the last part of a mob farm and are used to kill mobs in massive amounts while also collecting all dropped items at a convenient location. They are a mechanism and can be considered a special type of trap.

Mob grinders are sometimes specific to a certain size of the mob. Tall mobs usually refer to tall hostile mobs, namely skeletons, zombies, and creepers, but can also refer to zombie pigmen. Small/short mobs are only 1 block tall and are spiders, pigs, wolves, chickens, cows, sheep, and ocelots.

Squid and ghasts have unique behavior, spawning conditions, and/or size making them difficult to grind. Therefore, they are often omitted when someone says 'all mobs'.

Mob grinders will not produce music discs or rare drops as the mob deaths do not meet the conditions for those items. However, if built in a particular way the conditions can be favorable to induce such situations, but will require the player to impart minimal input in such instances.

Fall damage grinding
Fall damage is one of the simplest and quickest methods of mob grinding. This method is often done in combination with a mob farm where the mobs are forced into water streams and can easily be dropped from a lethal height. Some mobs, such as those which can fly, are immune to fall damage. Notably, these include blazes and iron golems. Most common mobs, however, can be killed with a 24 block drop.

Arguably the most important aspect of a fall damage grinder is the drop height. Different mobs need to be dropped different distances in order to kill them. Some mobs such as zombies and skeletons can occasionally spawn with Feather Falling boots or armor which may change the required distance. Because of this, it is often better to make the drop further than necessary.

When using a fall damage grinder, it is often desirable to kill the mobs manually in order to obtain experience and other exclusive drops. By dropping the mobs slightly lower than the minimum death height, it possible to make most mobs end up with health points, the ideal number before you deal the finishing blow. Note that $$ it is not possible to bring zombies to half a heart, even with a combination of falling and suffocation, because zombies have natural armor points. If you wish to use your fist rather than a tool to kill the mobs, a strength beacon may provide the extra damage necessary to kill zombies and mobs with armor in a single hit.

Spiders can be tricky to deal with as they can grab the walls and reduce fall damage. To kill spiders, a minimum of a 2&times;2 pit is necessary. You may want to dig the pit deeper than the required 19 blocks in case a spider does brush the wall at some point in its descent.

Tips:
 * Bubble columns are very useful when getting the mobs up high enough to drop.
 * If dropping the mobs to kill later, make an opening showing just their feet so they can't attack you.
 * Witches and endermen must be killed immediately or the witch will heal and the enderman teleport.
 * Magma blocks may be useful to kill Feather Falling survivors.

Common Styles
The following are the most common styles of mob grinders. They are efficient and relatively small.

Lava grinders


While lava is good at dealing damage, it also tends to destroy items. The loss of items can be avoided by suspending the end of the lava stream on a sign and pushing the mobs into it. When a mob dies, its items should then fall below the lava and into the hopper. This type of grinder is often called a "lava blade."

Instead of pushing mobs into the lava, it is also possible to temporarily douse them using a dispenser. During the short period of time in the lava, the mobs catch fire and are weakened until a player can easily kill them with one or two hits.

Piston grinder


Using pistons, it is possible to push blocks into mobs so that they suffocate. In the shown example design, a piston pushes a mob underneath a sticky piston holding a block. The sticky piston extends at the same time to "smash" the mob and cause it to die from suffocation at points per second. The water used to push the mobs can also be used to wash the items to a hopper for item collection. This setup only works for tall mobs, but the same principle can be used for smaller mobs as well.

The downside to this trap is the slow rates of kills, since each mob needs about 10 seconds of suffocation before it dies. This problem can be fixed by having a row of pistons push together at once, suffocating multiple mobs in every smash. Another downside is the inability to handle spiders. You will need to find another way to sort out spiders, such as a cactus choke.

Timing is very important for this trap to work efficiently. For single mob smashes, a loop of at least 30 repeaters set at maximum are needed, giving 12 seconds per loop. With this setup, turn on the loop for a little more than 10 seconds to ensure they die, and have the loop off for the rest, giving 10 second kills and 2 second load times. For a full row of 8 pistons, the load time is approximately 6 seconds, meaning the loop needs to have 40 repeaters giving a 16-second loop. Load time for a stream of 8 blocks long and 2 blocks wide, with pistons on both sides, is about 8 seconds. This amounts to at least 48 repeaters.

Magma blocks
Magma blocks are a very simple method of mob grinding. When mobs walk on a magma blocks, they are dealt damage every second. This means an unarmored skeleton will die in about 20 seconds. To avoid being damaged while building, you should obtain Frost Walker boots, drink a Fire Resistance potion, or just crouch.

Although magma blocks do not destroy items, collecting the items can be a little tricky. There are generally two options for item collection: Use water streams to wash items off the magma blocks or use hopper minecarts. Water streams have the downside of negating any fall damage and potentially causing the mobs to bob up and down, only taking damage some of the time. Running hopper minecarts on rails underneath the magma can solve both of these problems but is more expensive.

Not all mobs can be easily killed by magma blocks. Nether mobs, such as wither skeletons and blazes are not affected by fire damage, so magma blocks are not useful as a nether grinder. Magma blocks are also ineffective against witches as they drink fire resistance potions negating damage. Spiders can also be tricky as they may climb walls and cause issues.

Trident Killer
Trident killers are completely automatic, but the mobs drop items and experience as though they were killed manually. They work by throwing 1 or more tridents onto the ground, and having pistons push the trident(s) around. When the moving trident makes contact with a mob, this tricks the game into thinking that you threw a trident at the mob. As a result, the game registers this as a player kill. In multiplayer, whoever threw the trident(s) must be on the server for this to work.

The trident never despawns, meaning that it can remain in the kill chamber. Because the trident only needs to be thrown once, it does not run out of durability.

If the player holds a Looting sword while using a trident killer, the enchantment is applied to any mobs killed by the farm. In multiplayer, the player who holds the Looting sword must be the same as the player who threw the trident(s).

Many advanced players consider trident killers to be essential to mob farms, since Bedrock Edition does not yet have the sweep attack. They are more difficult to build in 1.13.0 and later, due to, but are still possible.

A slightly more advanced design pushes the items and experience out of the kill chamber. This allows for farms with multiple trident killers, all of which deliver the experience to a single AFK spot.

Alternative grinders
The following grinders can be effective in the right situation but are less common due to size, inconvenience, or other disadvantages.

Mob Stacking Grinder
This trap consists of a single minecart rail at the bottom of a 1x1 pit that has 24 minecarts placed upon it. Water can be used to transport enemies into the grinder from above. They will be unable to jump out as long as the pit is at least 2 deep. The track and carts can be placed on top of a hopper to collect any items that are dropped. This grinder deals a lot of damage: skeletons and zombies die in about 2 seconds of exposure. It works by reaching the mob stacking limit of the game. When too many entities are shoved into too small a space they become damaged.

The downside to this trap is the high expense, since it requires 120 iron for the minecarts alone. Its also annoying to remove if the player needs to make changes to their trap. It also generates a lot of noise from the carts continuously trying to resolve their collision issues. Carrying 24 carts at once will take up most of the player's inventory so its somewhat inconvenient to transport.

The upside to this trap is it is extremely fast, compact, it does not destroy items, and is easy to combine with a hopper. It also works on mobs that are immune to fire and lava, such as zombie pigmen.

To place the minecarts efficiently it is recommended that you make a bottom block along one edge of the pit a half slab. This way you can easily access the rail on the bottom and place all the minecarts without losing line of sight of the rail.

Cactus choke
This cactus choke kills spiders, solving potential spider size/jump/climbing issues. It is a simple design, relying on the spider's 2×2 size. The grinder stops all spiders at a bottleneck, where the water-conveyor narrows from 2 blocks wide to 1 block. A cactus is placed on the side, on top of a sand block, where spiders will run into it.

Sunlight Death Chamber
Zombies and Skeletons burn in sunlight which can be an effective way of dealing damage and separating creepers. This can also be done with monster spawners, a tutorial is available. A sunlight death chamber is simply a room with a glass or a hollow ceiling. This is a very simple mob grinder to make but has several downsides:
 * Daytime. Only the sun can burn these mobs, making this useless at night and when overcast.
 * Unblocked. No blocks can be directly above the trap (with the exception of glass).
 * Dry. Water extinguishes fire and since the mobs burn, no water can be present in the chamber. This can be simplified by having a valve which can be shut off during the day.

Mob arena
Strictly speaking, this is not a mob grinder but does have a similar outcome and is a way of using the mobs spawned from a mob farm. The mobs are collected in chambers and slowly released into the arena to fight against players.

The concept is simple, 2 tall buildings, with about 15 rooms inside, that have holes at all corners, and water around the sides to push anything that goes to the side into the hole at the corner. Then once the mobs fall down, they are trapped in a simple holding area until a lever is pulled to let pistons open so that the mobs can fall out.

Video explanation and showing the concept at work:

Anvil Smasher
It is possible to grind mobs by smashing them with an anvil. To do so, they should be contained in a small, inescapable chamber (preferably 1×1) with an open ceiling and a tall pillar on one "wall" of the chamber (the more placed, the more efficient). Then, a player may climb to the top of the tower and drop an anvil into the hole on top of the mobs. If they are dropped from a sufficient height, all mobs will be instantly slaughtered. Players may collect drops by means of a hopper or by going in. The anvil will, however, need to be manually retrieved. A way to bypass this would be to place a torch or sign at the bottom of the shaft to destroy the anvil straight after killing the mobs. Again, using a hopper would bring it back to the player along with the loot.

Basic collection
To retrieve the drops without any chance of despawning, put a hopper in the ground/floor at the end of your water flow or wherever your items drop out. Put a double chest under the hopper, and make sure to go empty the chest before it fills up and items pile up outside. The simplest way to do it: W=Water, O=Air or Block, H=Hopper

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Hopper item collection
Build a hopper platform under a mob farm, where mobs will fall to death. Hoppers automatically retrieve the loot and can be connected to chests to store it in several ways.

Railroad item collection
The player can make a mob farm in the air and then set a platform area where mobs will fall to death. To retrieve the resulting loot, they can build a railroad system in such a way that they will be automatically retrieving all the loot while being AFK (away from keyboard or screen). Falling mobs will hit the player and could stop the riding, so it's important to have the smashing area covered with powered rail and the curves made out of normal rails should be out of reach from the falling mobs.

Videos
de::technik:PH Monster-Fallenanlage 教程/怪物磨床