WikiGoon
A WikiGoon is a troper that works rather hard at dealing with vandals, often by leaving a not so subtle hint on a vandal's userpage they they need to cut it out or they'll get banned. They also tend to informally enforce the rules when a discussion gets unruly by telling everyone to cut it out or they'll get reported to an administrator.
Whats separates them from WikiKnights is that this troper prefers to settle things informally by warning the vandal, where the WikiKnight prefers to do so by informing the administrators first. The WikiGoon is also not as polite as the WikiKnight and takes it badly when vandals ignore them and continue their mischief.
On All The Tropes, this sort of behavior is frowned upon, to the point where a persistent WikiGoon can be banned for threatening other tropers.