Thrax is the main antagonist of the 2001 animated movie "Osmosis Jones". He is a deadly virus that enters the body of a zookeeper named Frank DeTorre after he eats a hard-boiled egg contaminated by chimpanzee saliva and mud. Thraxs main goal is to kill human bodies so that he can set a record for the virus to kill a man the fastest and be written about in medical books. He is determined to kill Frank DeTorre within 48 hours. Thrax kills his victims by stealing their hypothalamus, which he stores inside a necklace. He has the ability to cause cells, germs, and objects to catch fire with his claw.

There are different theories about what kind of virus Thrax is. According to one theory, Thrax is a human immunodeficiency virus because Frank touched a chimpanzee before he caught Thrax. Another theory suggests that Thrax is a cytomegalovirus that has become lethal because cytomegaloviruses are DNA viruses, and they exceptionally attack the brain. A third theory is that Thrax is the rabies virus because he attacks the brain. However, it is not clear what kind of virus Thrax is.