Mob added in Minecraft 1.8. Endermen are black, neutral mobs from the End that have the ability to teleport.
Endermen spawn on solid blocks at light level 7 or less. They spawn commonly in the End in groups of 4; however in the Overworld they spawn in packs of 1-4 and are rarer than most other mobs.
Endermen may drop 0-1 ender pearls (or up to 4 with the Looting enchantment), and 5 experience orbs when killed by a player or a tamed wolf.
In 1.9,[upcoming] endermen holding a block will drop that block.