You know how in the center of a minecraft screen there is that cross? If you look at them with that, they will not rest until you die. They hurt you if they touch you, and they can teleport around to follow you, even into your house if it is tall enough for them to get in. Personally, they are my favorite monster. I like that if you stay out of their path, they'll stay out of yours.
Oh, okay. I never noticed the little cross thing, but then I was too busy laughing at the hilarious dialogue of the players to see it. But it makes so much more sense now that I remember it. The enderman just popped up out of nowhere and started following one character constantly. I've never played the game, but watching it was awesome. Thanks for the info!