He was deployed against Fight-Man and Agent X by Beverly Lacoco and The Hooded Eye. Both Agent X and Fight-Man couldn't stand up to the sonic sound of his beat-boxing. Therefore, Agent X had Fight-Man rip his ears off so he could fight without being effected by the sound.
Ill Billy was severely beaten across the head with a baseball bat by Agent X. The impact cause him to bite his tongue off. He fell to the ground and was left in an unconscious heap.
Ill Billy is a mutant with the ability to beat-box on a sonic level.
Sonic Scream - Ill Billy has the ability to create a sonic scream strong enough to shatter windows and severely damage people's ears. He uses his ability by beat-boxing and it is not known if he needs to beat-box to do it or not.