Chemo is a walking toxic waste vat with minimal intelligence. The only reason that he is sometimes difficult to defeat is because he is radioactive and can spew radioactive waste from his mouth at his enemies.
Seeking to conquer disease, famine and all the ills of mankind, Professor Ramsey Norton experimented endlessly with various chemical combinations, disposing of the results of his failed experiments by tossing them into a large man shaped plastic mold Norton called Chemo. Norton felt the presence of a humanoid chemical filled form would remind him of his failures and thus urge him to swifter success.
While experimenting with the concept of unchecked growth for fruits and vegetables as a cure for famine, Norton poured the results of his failed attempts into Chemo, filling the plastic figure at last. The exhausted professor fell asleep at his desk after deciding he would have to empty Chemo the following morning.
An unholy gurgling noise awakened the slumbering scientist, and he turned to find Chemo growing larger behind him, apparently taking on a life of its own. Before Norton could make a move to reverse the process, Chemo spit out a stream of volatile chemicals that incapacitated Norton and ultimately killed him.
Now possessed of some primitive malevolent intelligence, Chemo began a rampage of destruction that was only halted by the timely intervention of the Metal Men. Though seemingly destroyed by the Metal Men, Chemo has returned to life time and again to continue his campaign of destruction.
During the Crisis on Infinite Earths, Chemo killed Tula, the second Aquagirl. Although these events happened before the restrucuring of reality, a version of them still seems to have happened. Chemo was defeated by Negative Woman here, who shattered his plastic shell. Shortly after, it returned by healing with Superman's cells, who defeated him. Following that defeat, Chemo was not seen for some time. When he did return, he menaced Leesburg, home of Linda Danvers. Chemo now had the metal pieces on him that he has kept ever since. Danvers defeated Chemo by telling it that it wasn't human. Horrified, it dispersed into a harmless rain shower. Chemo is reformed sometime afterwards, in which it is used in the Suicide Squad by Lex Luthor, under Manchester Black's guidance to fight against Imperiex. It is destroyed by its "teammate" Doomsday
Chemo was dropped on Blüdhaven by the Secret Society, making the city uninhabitable. This time, Superman defeated it by hurling it into space. Most of the poisons in the city were reabsorbed by the beast, but not enough to make the city habitable again.
While in space Chemo is attached to S.T.A.R. lab research station. The the scientists try to use Chemo's powers for good but it back fires and they created smaller Chemos. These Chemo spawn kill the crew. It takes the combined efforts of Captain Boomerang and Nightwing to stop them and save the station.
Chemo was one of the villains sent to planet Salvation. Chemo was used again by Amanda Waller in a Suice Squad mission. She was programmed into Chemo and her likeness was in place of his face. When she was shot by Cliff Carmichael she lost control of Chemo and he began to destroy everything in his path, before being contolled by an injured Waller. The uncontrolled Chemo blasted Wndfall and the chemicals continued to spew forth eating away at her shield until her skeleton dissolved.
A monster based on it was fought by Frankenstein. Instead of being filled with hazardous waste, it was filled with "smart" water. The beast went rogue, attacking a town and driving it mad. It was destroyed when its shell was punctured by Frankenstein's gun.
So called Baby Chemos- smaller versions of Chemo colored red, blue and green- were stopped by Lightray and his Young Gods when visiting Metropolis. They were later linked back to Lexcorp.
Chemo was later seen under the capture of Simon Stagg. How he aquired Chemo is unknown. Java puts Metamorpho inside Chemo, bringing him back to life and therefore goes on a rampage. Owlman and Freight Train stop him and Metamorpho is saved. What happens to Chemo afterwards isn't specified as well.
An unknown individual steals on of Doctor Will Magnus' prototype responsometer and throws it into a vat of toxic waste. The toxic waste creates Chemo and he begins to attack Will Manus and the Metal Men. They enter Chemo and the metals join with the toxic waste making Chemo inert. The reaction was an explosion and only the respsonsometers were left.
Powers and Abilities
Chemo is able to spew toxic chemicals. He is also able to reform his body when destroyed.
Batman: Brave and the Bold
Chemo appears in the episode "Journey to the Center of the Bat!" in which the Brain uses Chemo to attack a seaside city and hold it ransom. Ryan Choi and Aquaman are forced to shrink down and go into Batman after Chemo poisons him, befriending a white blood cell and naming it Platelet along the way. It is destoryed when Batman blows up its plastic shell.