Head

Mob heads are decorative blocks. There are five variants of mob heads: Skeleton, Wither Skeleton, zombie, human and Creeper. The Wither Skeleton variant is a rare drop from the respective mob, with the other heads only available in Creative mode.

Uses
The main use of heads is as decoration. They can be oriented in 16 different directions on top of a block, and 4 directions on the sides of blocks, similar to signs. They cannot be placed on top of each other.

Wither skeleton skulls are essential for spawning a Wither. To do so, place 4 soul sand in a T-shape, then place three wither skeleton skulls on top. The orientation of the skulls does not matter.

Heads are also used in the crafting of Firework Stars. Firework Rockets crafted with said stars will have a creeper shaped explosion, regardless of which type of head was used.

The player can also wear heads as disguise, similarly to pumpkins. This will only replace the first layer of the player's skin. If the player has a second layer over their head, it will still render over the head. Occasionally, another mob may pick up a skull and wear it just as the player would. This is common when a wither skeleton drops a skull next to another mob in the nether. They can also be used as a decorative disguise, using dyed leather armor. Heads are not able to be pushed by pistons, as they have tile entities.

The only mobs which can wear the heads are the Skeleton, Wither Skeleton, Zombie, and Zombie Pig Man (Only the part that is skull shows). As of right now no other mobs can wear the heads. However, other mobs can wear heads using custom spawners via MC Edit.

Trivia
Note* Using the and other inventory hacking commands to give the player a mob-head block (ID 144, not 397) will give the player a flat-looking soul sand.
 * When breaking any head, the particle effect of breaking it is the same as soul sand.
 * All heads are not to scale, but are, in fact, the same size (even though Wither Skeletons have larger heads than the other represented mobs).
 * Heads are one of the few blocks that do not use terrain.png and take their textures from other objects.
 * Heads will break upon contact with water and lava.
 * If you were to change the texture of a mob's head, the head will change too but will not render hats.
 * Heads can be worn by zombies, skeletons, wither skeletons, and zombie pigmen.