The creepiest thing about this story, is the fact that it's true and isn't unrealistic in the slightest.
Happened about half a year ago to a friend. He'd been out partying, and then too much alcohol and he blacks out.
He woke up on a bare mattress in a room he doesn't recognise, completely naked on the bottom half, missing his wallet and mobile phone. He's also absolutely covered in scratches and bite marks.
Understandably, he freaked out but decided he has to get out as quickly as possible. So whilst trying to find a way out, he found the front door. It was blocked by metal bars.
By this point he realised he is in deep shit. He went back to the room he was in, climbed out the window and had to scale the building to the next apartment with an open window; which he sneaks into, steals trousers and get's the fuck out of.
According to the people he was out with, the last time they'd seen him that night, he'd been speaking to a really old man. Strange.