(n) A mice eater is a insult. It means that someone enjoys eating mice, or it can simply mean that someone is a little strange or weird. Mice Eater, therefore can be taken in a nice way or in a rude way. It just depends on the context. The word can also be a name when someone is trying to flirt by being rude.
The guy, Quint, was in the hallway opening his locker. Then another guy came up to him and the guy said, "Hey you mice eater," Then Quint became scared and afraid so he just laughed.