The hyperactive bully is like a firecracker — he can go off at any second. This type of bully is usually a high-strung child who struggles both academically and socially. He may have a learning disability or attention deficit hyperactivity disorder that makes it difficult for him to exercise proper impulse control. This type of bully doesn't have many friends and will act aggressively at any perceived hostile act of a classmate, regardless of the actual intent.

Carl is uptight, unpredictable, and is considered to be a high-maintenance kid. Some days Carl manages to behave just like a regular kid — one of the gang. On other days, Carl is like a volcano ready to erupt. On those days, the other kids in the class walk on eggshells around Carl.

But things are lively and active in a fifth-grade classroom, and on one of Carl's off days, all it takes is for one of the boys to bump into Carl and — Pop! — he explodes. Carl will holler insults, push the offending boy away, and be primed for a knock-down, drag-out fight. His overreaction frightens some of his classmates.

And once someone “crosses” Carl, he's quick to react in a dramatic and negative way in the future. Carl doesn't intend to be a bully, but his excess energy, his lack of proper impulse control, and his frustrations over his learning difficulties often exacerbate his volatile nature.