Nightmare Enderman

Note that this does not exist in Minecraft; it was written purely as a fiction article.

Nightmare Endermen are evilish, dark purple versions of endermen. They have recoloured eyes. They make higher-pitched endermen sounds and make a zombie pigman's hurt sound when hit. Their eyes glow in the dark.

Tactics
Nightmare Endermen are found when it is killed by the Ender Dragon or an Ender Creeper. They are twice as fast as regular endermen and twice as many hearts. They can pick up blocks and throw them to deal damage. Once one is attacked, it will never stop giving chase, even when after running several kilometers. They will teleport about once per second and can actually pick up players and throw them, dealing a small amount of damage from the fall, similar to Iron Golems. The player only needs to be in a 36-block radius to be seen by a Nightmare Enderman.

Habitat
Nightmare Endermen do not spawn naturally, but are seen in The End, unless an Ender Dragon is hacked in the Overworld and it kills an enderman.