Enderman

The Enderman is a mob introduced in version 1.8; The Adventure Update. The Endermen are depicted as 3 meter tall, black creatures with long arms and legs. They also have the ability to pick up and move blocks around. They are generally peaceful. If you look at them, by placing your crosshair directly over them, they freeze, stare back at you, and become hostile. They stay frozen as long as you keep looking at them. When you look away, they will quickly run towards you; if they are a long distance away, they will teleport several times until close enough to reach you. Endermen can teleport about once per second.

Trivia

 * The name "Enderman" is derived from the internet phenomenon Slender Man, due to the mob's similar looks. Its name was given by Notch in a Reddit thread.
 * Due to the Slenderman relation, many have petitioned to change Endermen to "Farlanders". Notch has stated however that he will not change their name, regardless of this petition.