The scariest monster in gaming

[MasterOfHisOwnDomain]

Anything that's been in Silent Hill, pretty much:

Spoiler

 

[Biosophilogical]

The troll in the first Harry Potter game on the playstation. I almost had a panic attack every time we got that far in the game (and I have never had a panic attack before, so a) I'm only guessing and b) Holy shitting balls! Never again!)

OT: The sharks on the beach/pirate level of Banjo Kazooie. I couldn't stand being in-game underwater since then until I played Monster Hunter Tri and was able to actually fight back.

 

[octafish]

Psi Monkey, Cyborg Midwife, Shodan herself, they are all scary. I would have said Captain Price though.