Doctor Trap was once Larry Trapp, a man who lost his beloved girlfriend Caroline Anders who was killed in the crossfire of a battle between The Justice Experience and their enemies , The House of Pain. He blamed all the parties involved for her death and swore revenge on them all. He later went about trapping and killing various members of both teams including the leader of the Justice Experience, Walter Chase, who was known as The Acro-Bat. He killed Chase by ripping out his throat with his cybernetic jaws and left him on his kitchen floor for his family to find; Walter's eldest daughter Cameron was the first to find him. This incident, and by extension Trapp himself, is responsible for causing Cameron Chase's deep seated hatred of super beings.
Years later it was revealed that Trapp was still alive and still seeking revenge on the Chase family. He kidnapped Cameron's sister Terry and tied her up at a wax museum for Cameron to find. Cameron is also captured when she comes to Terry's aide. They are both saved by the last minute by the intervention of the current Manhunter's assistant, Dylan Battles in an old version of Batman villain Firefly's battle suit.
Later, Trapp had convinced his keepers at the prison that he was reformed, and they called in J'onn J'onzz to psychically verify this. Trapp had manipulated Bette Noir and conditioned his mind into a trap for J'onn. He then escapes while the Martian is incapacitated, seeking out Cameron once more. A recovered Manhunter from Mars arrives in time to help defeat him. J'onn places Bette, who's own body had been killed by Trapp, into his mind, turning his own snare onto himself, simultaneously saving Bette. J'onn stated he would later rectify both of their conditions.