alma was unsettling. the fact she doesn't hurt you is irrelevant; when you're already tense and you turn a corner to see a girl who liquefies people with her brain rushing at you like a crab it tends to make you swear loudly and empty your clip at the floor where she was a second before.
fettel was a bit creepy too. the nightmares were scary when they popped out the first time, but after that were just ****ing annoying there was no kind of suspense/buildup or anything else, they just warped in front of you and fking killed you. the spectres in FEAR 2 were generally creepy, with one particular sequence of downright terrifying.
running into a tri-gen up close is never fun. the first encounter with the flood in HALO was good, but they also became annoying rather quickly.