Spooky Hot
Someone or something that is frightening, creepy, or otherwise disconcerting, but still possesses an undeniable undercurrent of sex appeal.
Examples are gothic chicks, young hitchhikers, and -- I quote from the originator of the phrase -- "The Ice Queen from that Narnia movie."
"This creepy guy on the highway asked me for a ride. He was spooky hot, so I said okay."
"This creepy guy on the highway asked me for a ride. He was spooky hot, so I said okay."