Has anyone played the WH40K: Firewarrior game? No?
Allow me to explain. Towards the end of the game you have to explore this chaos temple, and everything goes a bit Doom like. Anyway, some enemies arrive by teleporting right in front of you and opening up in your face. Some of these enemies even have the audacity to carry rocket launchers. So you'll be walking along a corridor, and SUPRISE! You've just lost most of your health.
The worst part is that even when you know they're coming, you can't always dodge in time. There is, quite literally, a bolt of red lightning, and then an enemy is there and pointing his gun right at your face. They don't even have to aim. They just fire. Actually, I correct myself. The worst part is that sometimes they think it's funny to then pretend to be dead. So these guys get to suprise you twice. With rocket launchers. Come to think of it, there were a lot of cruel enemies in that game, that I may tell you all about some other time.