Origin
Marcus Simms was equipped with a symbiote which was separated from Hybrid. He is part of Mercury Team.
Creation
Marcus Simms was created by Zeb Wells and Clayton Crain
Major Story Arcs
Marcus Simms debuted in Carnage USA as part of Mercury Team. He uses the symbiote known as Lasher as a weapon. He is sent after Carnage when he abducts the entire town of Doverton, Colorado.
Mercury team was slaughtered by Carnage, and the symbiotes used the dog to transfer themselves to Deadpool.