Bullwhip aka Harold is a teenager who kidnap Dr. Coros's wife to make the doctor turn him into a cyber enhanceted gang. He also made him to do it with his gang. Later, Batman and the doctor finds out that the doctor's wife is having an affiar with Bullwhip. Later, Batman defeats Bullwhip's gang causing to Bullwhip to escape. He went to the doctor and asked him to make him stronger, unaware that the doctor found out about him and his wife.
The doctor stated that he wont be holding back (meaning he's going to kill him).
He appears in Batman Beyond
Brace Wayne stated that Bullwhip won't be coming back.