Enderman

In a Google+ post, Notch revealed a mob called an Enderman. Endermen are depicted as tall, black creatures with long arms and legs. They also seem to have the ability to pick up and hold blocks. They are generally peaceful. If you look at them, they freeze, stare back at you, and become hostile. When you look away, they will run fast towards you and teleport.

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.