There was a guy in camp when I was fourteen who started giving girls hickeys as a joke. One night a bat flew into the cabin where several of us were chatting. This guy was absolutely terrified of bats and immediately ran behind a curtain for cover; he didn't realize that I also was behind that curtain. As he was peering fearfully round the edge of the curtain watching the bat I bit him on the shoulder. As an act of unplanned revenge it was very satisfying.