The most terrifying enemy in games?

[Moot]

-The- single-most terrifying enemy in any game ever created that I have ever seen?
[url="http://metroid.wikia.com/wiki/Nightmare"]Nightmare[/url]- Metroid Fusion.

Here's a video of the fight. The music really sets the tone.
[url="http://www.youtube.com/watch?v=4O6tICXqwfk"]Creepiest. Enemy. Ev4r.[/url]

[doady]

I remember the enemies in the original Diablo being pretty creepy, especially the Hidden. And then of course there was the Butcher. A creepy game overall.

[tammy922]

I hate beholders and liches. I really hate beholder liches, lol.

[VoodooDali]

Weasel