Not an enemy per se but a game. Fatal Frame 3. That thing scares me and I think it´s the only game that can do that to me. Back in the day, I really hated the Hunters from RE. You could hear them walking around and you knew, one wrong move and you´re dead
The crimson heads were pretty nasty too with their insta-rise-and-claw-your-fucking-head-off and whatnot