Enderman

Endermen are neutral mobs who are three blocks tall. They are also the tallest mob in the game.

Behavior
Endermen can damaged by water and will teleport away when they take damage. Endermen don't attack unless provoked by a player attacking them or looking at their bodies or upper legs from up to 64 blocks away. When provoked, endermen will open their mouths and shake with rage; when provoked by being stared at, they will also make a lengthy, loud, threatening sound and will quickly move towards the player to attack. If an aggravated Enderman is hit by another mob such as a tamed wolf, it will cease attacking The Player.

They can also step up one full block without having to jump.

Endermen will continue chasing a player until they are either killed, sustain several hits, or become distracted by exterior elements like fire or sun; they are likely to teleport away to underground locations, such as caves and mineshafts, at day break.

Enderman Spawn in the nether as of 0.15.0

Endermen can't be provoked by players looking through transparent blocks or from within a minecart.

Trivia

 * Endermen cannot be damaged by shooting with arrow, throwing eggs or snowballs at it.