Devil Crabs
A sexually transmitted bug, crabs, which are red and you get from having sex with the devil. More used as a joking term by high school freshmen, devil crabs are more often than not, said to be had by a freshmen who has had sex before they turn sixteen.
Jane:I've got crabs.
Jenny:You've been sleeping with too many guys. 
Jane:I think they're red.
Jenny:That's gross. What? Did you have sex with the devil and now you have devil crabs? 