A villain named Dr. Sugarman broke into his lab and tried to steal the virus. David was injured and injected with the untested virus. He became Xombi, a technologically enhanced human being who battles the Shadow Worlds. At one point he was part of Star Chamber with Rocket, and has appeared since the merger of the Dakotaverse into the DC universe.
He was the first Milestone character to confront Dr. Nemo.