"Metalmouth" was once an ordinary, if a bit high-strung, metal shop teacher at Lawndale High back in the early 80s. Legend had it that he would grind his teeth when his students got on his nerves, which was often enough that he eventually ground them down to nothing. Unable to bear the students' taunts at his lisp, he built himself a set of steel dentures.

Unfortunately, the dentures picked up radio stations, particularly when they were playing Cyndi Lauper's "Girls Just Wanna Have Fun". Naturally, the students laughed at him even more, with the result that he hid himself in the woods and attacked their cars when they stopped to make out, biting the tires and door handles.

The story of Metalmouth is told by Jane and Trent.

Metalmouth may still be out there, as Helen's car bore traces of his attack after the story was revealed.

Metalmouth strongly resembles Mr. DeMartino.