Look at those things. Actually, wait, don't! If you look directly at them in Minecraft, they'll come for you the second you look away; otherwise, they are totally passive. Also, teleportation -- these things can do that, because of course they can. Someone, hold me!
These Endermen, as designer Markus Persson calls them, are being introduced in the Adventure Update.
He believes that creepiness is "more about trying to avoid something from happening than it is about actually having that thing happen. If you know something bad can happen if you do the wrong thing, you will start thinking about your actions, and that might make things more scary.
The psychology of the reticle and the feeling of control [The Word of Notch via Rock, Paper, Shotgun]