The creepiest thing I can think of? A great big hairy black spider sitting in my bath. And this sums up my fear ...
And your avatar is a big scary dragon... Something creepy? I've got a box full of spiders - and I know where you live...
Spiders are real. Dragons are not. I know that because I've been bitten by the former, but not by the latter. Thank you, but no, thank you. Being arachnophobic, I'd rather not receive any spiders.
Have you ever noticed that when you're alone in the house at night, and the house sort of creeks, it sounds louder then it usually does when there are other people in the house? Oh, and my one relative's basement. I dunno why, nothing bad ever happened down there and it really did just look like a normal room, but whenever I was down there alone I got this uneasy feeling that I was in danger and that I should be upstairs.
I've been in basements that affected me that way. Gradually realized there was only one way out of all of them, and that was what bothered me.
Not so much creepy as unsettling. Lost, walking down a corridor in a hospital, arriving at the door at the end. A coincidentally arrving doctor opening said door, and asking if I was coming in. Looked up at the sign above the door, which said "Morgue".
Unsettling, yes, but not as unsettling as what it would've been like if the sign said "Borg". (And I don't mean "Bjorn")
Something small quietly accusing you of being a bad person. Like you're passing by an electronics store, and one of the smaller TV screens says your name and that you hurt someone.