Carl had lived a life in poverty, faking wealth in order to get into the scientific community.
He later worked with David and Tina and considered himself David's rival for Tina's affections. However he had ended up accepting their relationship when they left on a trip to get closer together.
Carl prepared a lecture years later after David's death where Tina and her friend Barry Allen attended. Unknown to Tina, Carl used his time in Central City as a way to test his experiment of replicating David's work out on the homeless. Murdering many victims. Carl later got closer when he stole David's notes from S.T.A.R. Labs. Using the finished formula on his dog, Carl used this distraction as a way to get away to test it again on a rabbit, but the Flash caught up to him. David outsmarted the Flash in order to buy enough time to inject himself with the formula. He then proceeded to kidnap Tina. Tina begged him to stop, because her husband had died after using the serum on himself. Carl said that she didn't understand, but that she would. He then attempted to inject her with the drug, but the Flash saved her. He then went on a rampage throughout the ghetto district of Central City but was defeated when the Flash wrapped a chain-link fence around him, immobilizing him until the serum's effects wore off, causing him to revert to his normal appearance.
- Meta-human physiology: Carl had mutated his DNA after injecting himself with his experimental serum. He had then gained superhuman strength from his newfound power.
- Superhuman strength: Carl's strength had vastly increased when he injected himself with the serum. Being able to throw police cars with ease, break doors off their hinges, and throw people medium distances. His strength was even powerful enough to stop the Flash while he was running.
- Superhuman durability: While not strong enough to withstand blows from the Flash, Carl was able to be hit by a car with no effect while injected with the serum.
- Time limitation: Carl's serum could only last for a limited amount of time before having to take another dose.