Thrax is the main antagonist of the 2001 live action/animated Warner Bros. film, Osmosis Jones. He is an extremely virulent, one-of-a-kind virus, whose goal in life is to kill all his targets faster than the previous one, to make sure that history would remember him as the deadliest virus known to man.
In the beginning of the movie, Thrax enters the body of Frank De Torre, a widower without the slightest regard for hygiene and health, right after he eats an egg that had monkey saliva on it and then fell on a muddy floor. He then enters Frank City, a city inside Frank's body where all his body cells are living a life identical to that of humans. Thrax quickly takes control of the many gangs of bacteria present and plans to take advantage of Frank's poor health condition to operate undetected.
Osmosis Jones, one of Frank's white blood cells who acts as an elite police officer, and a cold pill named Drix soon discover that something dangerous is going on,