That snake looking thing that hangs on the back of a shaved kids head, usually stemming from gangster parent's or brown lip liner wearing mothers. Rat-Tail may further be used as a name that represents whoever sports it. A patch of hair that for some odd reasons signifies god knows what while the bald part is covered with a panty hoe or doo-rag!!! Originated in L.A. usually in hispanics and has viciously infected young children's schools across the nation. These kids are known for bullying and cursing in class.
A fight broke out in class, that lil rat-tail stood up and told the teacher off.
Another (better) reference for the ATV "mongoose" in Halo 3
Dude, forget the Warthog! Jump on the Rat-Tail!!