Funvac
A funvac is someone who can suck the good time out of any situation with their comments and/or actions,someone who can't take a joke.
You're hanging out with a few of your friends. Everyone is laughing and having a good time. You make one of your friends the butt of an innocent joke and everyone laughs. The target of the joke becomes annoyed and is now sitting there pouting and shooting off occasional nasty comments making it uncomfortable for everyone. You say "stop being such a funvac! It was just a joke...."