Chemo was a radioactive monster and biological weapon created, at first to solve the world's problems, but instead only became a source of them. Chemo was stolen by doctor T. O. Morrow who began experimenting to improve the danger that Chemo could possess, using his ex-business partner, Joker's Ace Chemicals Building to house the monster. When the Exobyte Heroes arrived to stop Morrow and the Exobyte villains were sent by The Joker to kill the Doctor for back-stabbing the Joker and stealing his "home", Morrow released Chemo on them, hoping the monster could do enough damage to buy him time to escape. The heroes and villains were able to overcome Chemo, and continue to push through the Ace Chemicals building.
Later, the Secret Society dropped Chemo on Bludhaven, transforming it into a radioactive wasteland with the toxic force of an atomic blast. The few people of Bludhaven who weren't killed in the attack or the resulting radiation were transformed into disgusting, violent mutants. Enraged at their heroes inability to protect them, the mutants attacked everything in sight. Smaller versions of Chemo, the Chemoids, began to form out of the radioactive waste the blast created. Horrified, Exobyte heroes and villains alike were deployed into the city as recovery teams and to put an end to Chemo- who still lived inside. After fighting through waves of Chemoids and mutants, the heroes and villains attacked Chemo and distracted it while the Hazmat Teams used their machinery to weaken the monster enough for them to directly damage Chemo, eventually destroying the monster. While the heroes were satisfied to have ended the monster so that cleaning and rebuilding Bludhaven could commence, the villains quietly recovered the remnant of Chemo to return to Amanda Waller.
- 1 Appearances of Chemo (DC Universe Online)
- 2 Images featuring Chemo (DC Universe Online)
- Quotations by or about Chemo (DC Universe Online)
- Character Gallery: Chemo (DC Universe Online)