Iron Golem

Iron Golems are large, 3 block-high, strong utility mobs. Their main purpose is to defend Villagers in NPC Villages from hostile mobs.

Creation
Iron Golems will automatically spawn in NPC Villages naturally, provided there are 15 Villagers. It does not have to be a naturally generated village; as long as there are 15 Villagers and a house, an Iron Golem will spawn.

The player may create them using blocks in a similar fashion to Snow Golems. To do so, the player must place 4 blocks of iron in a t-shape, and then place a pumpkin or a jack-o-lantern on top. This is equivalent to 36 iron ingots, making creation somewhat of a task. They will always spawn facing south.

Behavior
Iron Golems roam in villages rather slowly. When provoked, Iron Golems will move toward their target at a faster rate, swinging their arms up violently once in range to attack. This does 3½ to 10 hearts damage to their target and flings them into the air. They can take damage from lava, fire, poison, and drowning. They do not take fall damage. Upon death, Iron Golems drop three to five iron ingots, and sometimes one or two roses.

Iron Golems are able to hold roses and give them to Villagers, symbolizing the friendly relationship between the Villagers and Iron Golems.

Iron Golems will attack all hostile and neutral mobs if any come within their sight, except Creepers, Slimes, Magma Cubes, Wolves, and Ghasts. Iron Golems likely do not attack Creepers because of Creepers' destructive nature, which may destroy sections of the village. They will attack the player if the player attacks them first, or if the player attacks a nearby Villager (only in Survival Mode). The Iron Golem does not have to directly see the player attacking a Villager to become hostile toward the player. They do not despawn if the difficulty is switched to peaceful and will continue to attack the player.

Iron Golems have a larger than normal attack range, this causes them to be able to attack through a solid 1 block thick wall, even without line of sight to the target. If an Iron Golem generated as part of an NPC Village is killed, another will eventually spawn to take its place.

If a Golem is provoked by the player either attacking it or a villager, the Golem will become neutral again after the player runs away.

Defense
An Iron Golem's primary purpose is to defend NPC Villages from Zombie attacks, usually during a siege. Though slow, their high health and damage prove them to be great defenders. Player usage might involve enclosing Golems in a large fenced-off area to prevent their wandering off, although such control of the area could be accomplished in simpler ways.

Farming


It is possible to make a fully automatic iron and rose farm by building a "house" (see the trap example image below for details) for Villagers to spawn in. If an area is made where only Golems can spawn in, then a trap can be set up to obtain the Golem's drop items. Golems need a 2x2 blocks wide and 4 blocks high space (even though they're only 3 blocks high) to spawn and they spawn in a 17x17x6 area (see the spawn conditions image for details) centered in the center of the village (for maximal control, no nearby [which means in a 50x50 area] houses should be made, if you're making the trap near a natural village, or your house, make sure there's no doors so they won't be classified as houses).

When a Golem spawns, it should always spawn in the same place. From there, you can lead it to your trap (using pistons, water or the pushing of the Villagers themselves).

One Iron Golem will be able to spawn for every 15 Villager in a village. So 15-29 Villagers spawns 1 Iron Golem, 30-44 spawns 2 Iron Golems etc.. There is no limit of Iron Golems per village.

There are several ways to kill Iron Golems and obtain their drop items. The following are the most effective ones:

Note: A falling trap is not possible since Iron Golems don't take fall damage.
 * Drowning in water. Golems can't swim, so they will drown if their head is under water. Due to their high health, this is a very slow process.
 * Suffocation by a sticky piston and a block. The killing can start instantly after spawning but it will clock up the trap, making other golems unable to either spawn or die, depending on the design.
 * By lava that won't touch the Golems' feet (since this is where the drops appear). This is the most damaging (and therefore the quickest) of the automated killing methods. An example picture of this method is shown to the right.

If the Iron Golems are dropped at least 7 blocks below the floor block(s) of the house, they will immediately be outside the village boundaries, and therefore detached from the "village," so a new Golem will be able to spawn, even before the previously village-attached Golems have died.

If there is no other spawn space available, Iron Golems will be able to spawn inside liquids, meaning an instant drowning/lava killing trap is possible, as shown on the picture to the right.

Although dropping the Iron Golems out of the spawn boundaries as the first thing will result in a higher Iron Golem spawn rate.

The traps could have a collection area, where the player can pick up the drop items. It is possible to have multiple Golems spawn in one area to make a very effective farm.

Note: If your Villagers aren't spawning any Iron Golems and there's no other houses nearby, dropping water on the Villagers will update them, and force them to start the Iron Golem spawning, provided the spawn conditions are met.

If a player is short on resources and time but still wants to harvest the iron from Golems, they can simply suffocate the Golems with blocks of sand or gravel. Golems are very slow-moving and tend to wait at the same spot when not patrolling a village, so it is very easy to drop 3 blocks of sand or gravel on top of them and wait for suffocation.

An example of a very effective farm


The pros of this trap:
 * Needs very few resources, and no pistons.
 * The Iron Golem quickly exits the spawn boundaries (7 levels below house level is the grass level).
 * It uses lava (the quickest automatic method) for killing the mobs.
 * It has a collection point.

The cons of this trap: The way the trap works, is that the Iron Golems only have one spawnable space: the floor block used by the Villagers. The transparent blocks (they have to be transparent, otherwise they can spawn on those blocks as well) then catches them in flight and the Golem falls into the lava blade trap with a water stream looter. The reason the door has a wooden block on top is because Iron Golems can spawn inside doors as well.
 * It exploits the fact that cramped Villagers pushes anything that touches them a great distance, which may be changed at some point.

History
Iron Golems were first introduced in Snapshot 12w08a.

Bugs

 * When creating Iron Golems in a 3 tall area (the pumpkin directly against the ceiling), the block directly above the Iron Golem will break.
 * If an Iron Golem dies in lava, the block(s) of lava where it died in will be removed and the lava will not flow into those blocks even when they are filled with another block and it is removed.
 * If an Iron Golem attacks a group of Zombie Pigmen, the whole group won't turn hostile towards the Golem, only the one attacked.
 * If an Iron Golem falls into a 3x3 pit of water, it will spin rapidly.
 * An Iron Golem riding a minecart will ignore everything, even if a target is in attack range.
 * Hostile mobs do not attack the Iron Golem until the Golem attacks them.(might not be a bug)
 * An Iron Golem can spawn in a 2 block high area if the block above the two air blocks is glass.
 * An Iron Golem can spawn on half slabs and fences.
 * An Iron Golem spawned in a 3X3X1 space will immediately begin receiving suffocation damage. This will continue until the Golem dies or is 'released' from the tight space.
 * For some reason, an Iron Golem can swim out of a water pit in a case like this:

Trivia

 * Iron Golems spawn in a 10x10x10 radius. This goes for both natural and artificial villages.
 * As the population of a village increases, more Golems will naturally spawn.
 * The Iron Golems holding out roses to Villager children is a reference to the ancient robots in the Japanese anime movie Laputa: Castle in the Sky, as is the fact that the Golems are covered in vines.
 * When Villager children notice the rose in its hand, they will slowly approach, and take the flower eventually.
 * As with Snow Golems, the pumpkin must be placed last during the crafting process.
 * Also as with Snow Golems, there is no Spawn Egg for this mob. This is because the player can create them through other means.
 * It is implied by their looks and natural generation location that the Golems were created by the Villagers for defense.
 * Unlike other mobs (apart from the Magma Cube), Iron Golems will sink to the bottom of any liquid.
 * Iron Golems will avoid water whenever possible.
 * Iron Golems do not take damage when making contact with water (in contrast to the concept of iron rusting in the presence of water), but can still drown in the water.
 * When created, an Iron Golem spawns with a snow particle effect.
 * There is no maximum number of Iron Golems allowed per village.
 * Despite being crafted with a pumpkin head like a Snow Golem, the Iron Golem's head is made of iron instead of a pumpkin.
 * Iron Golems wobble as they walk, unique to other mobs which remain completely upright when walking.
 * Tamed Wolves will not be attacked by the Iron Golems if they are focused on the player.
 * Iron Golems have the second highest health points in the game, after the Ender Dragon.
 * The Iron Golem is the first mob that has its own attack animation with moving appendages.
 * Iron Golems can suffocate in a 2 block wide space even if their head isn't covered.