Iron Golem

Iron Golems are a mob created to defend NPC Villages from hostile mobs.

Creation
Iron Golems will spawn in NPC Villages naturally, provided the town is big enough. The player may also create them using blocks in a similar fashion to Snow Golems. To do so, the player must place 4 Blocks of Iron in a short T shape and place a Pumpkin 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 villages slowly and are passive to the player. 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.

They will attack Endermen, Zombie Pigmen, Blazes, Silverfish, Skeletons, Spiders, Cave Spiders, and Zombies if any come within their sight. They will attack the player if the player attacks it first, or if the player attacks a 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 do not attack Creepers, likely due to a Creepers destructive nature which may destroy sections of the village. They also do not attack Slimes, Magma Cubes, or Ghasts. It is possible for Iron Golems to accidentally attack one another, although this will deal no damage nor provoke them against each other. Upon death, Iron Golems drop three to five Iron Ingot, and sometimes one or two roses. If an Iron Golem generated as part of a NPC Village is killed, it will eventually respawn. They can take damage from lava, fire, and drowning. They do not take fall damage.

Defense
An Iron Golem's primary purpose is to defend NPC Villages from Zombie attacks. When attacking, they swing their arms as if tossing the enemy. The enemies are thrown up into the air and killed. Player usage might involve a large fenced off area inhabited by them to prevent wandering off, although such control of the area could be accomplished in more simple ways.

Iron Source
Although difficult to kill, farming Iron from them using respawning ones from NPC Villages is possible. This theoretically makes Iron a renewable resource.

History
Iron Golems were first introduced in Snapshot 12w08a. Before this, they were only implied as being created via artwork being done.

Bugs

 * Iron Golems will not attack Slimes, Magma Cubes, or Ghast. They may not attack Slimes due to their overabundance on Superflat worlds.
 * Sometimes, their texture will but to either pure white or invisible.
 * When creating Iron Golems in a 3 tall area (the Pumpkin directly against the ceiling), the block directly above the Iron Golem will break.
 * An Enderman killed by an Iron Golem will always drop an Ender Pearl.

Trivia

 * Iron Golem's heads are made to resemble the Villagers they protect. This includes their noses.
 * Sometimes, it will hold out a Rose to Baby Villagers. This is a reference to the movie Laputa: Castle in the Sky.
 * When Baby Villagers notice the Rose in its hand, they will slowly approach, and take the flower away eventually.
 * As with Snow Golems, the Pumpkin must be placed last.
 * 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 these were created by Villagers to defend them.
 * Unlike other mobs, Iron Golems will sink to the bottom of any liquid.
 * When created, a snow particle effect will display.
 * There is no maximum amount of Iron Golems per village.
 * Iron Golems are the second utility mob in Minecraft, after Snow Golems.