"Alri—hey!" Doc tried to scramble back as O’Malley reached down and started unfastening his shirt. He couldn’t move, however, because O’Malley was still straddling him. "What are you doing?"
O’Malley’s grin could have split his face as he undid Doc’s purple shirt, exposing the torso. “A signature. If we’re going to be entering into such a contract, I want to mark my property.” He twirled the shiv before resting the point against the middle of Doc’s chest. “Not to worry. It’ll bleed a lot, but the carvings won’t be lethal. However, they will be permanent.”
-Murderer’s Row, Chapter 128
All done. Bloody Doc is bloody.