He has reduced mental capacity, near superhuman strength and endurance, and is prone to outbursts of violence due to medical experimentation on his brain, chiefly the removal of his amygdala.

Anatomically, the amygdala refers to the bundle of nerve cells in the brain that control emotional associations of many kinds.

Easily led due to his childlike nature, Amygdala has been the pawn of a number of Batman villains, but when properly medicated, he can be peaceful.

2 #6 as a hulking menace when he tries to kill Mitch Shelley aka The Resurrection Man in Arkham Asylum, but is knocked hard on the head with Fletcher's nightstick.

After jumping out the window Aaron encountered and attacked a young Dick Grayson, who was out with his friends, away from visiting Haly's Circus.

In DC Rebirth, Amygdala appears as one of the many villains attempting to kill Batman to stop Two-Face from leaking secret information.

They are then attacked by Gotham Girl (Claire Clover) and the new Batman (Thomas Wayne from the Flashpoint timeline), the former of which uses heat vision to sear off Amygdala's arm.

His emotional instability and explosive rage enhance this even further, making him prone to bouts of boundless violence unrestrained by the usual barriers and limits set in place by one's self-awareness.