The Virus is the main antagonist in The Amazing World of Gumball episode, The Virus.
Virus and his army planned to infect Gumball, when Teri tried to make Gumball wash his hand. The Virus's army was washed away, and now seeks revenge on Gumball.
The Virus attempts to get revenge on Gumball for wiping out his army, but was distracted when fending off an army of germs on the keyboard.
Teri, Gumball and Darwin soon meet the Virus under a microscope, as Teri refers to him as a type virus that she's never seen before. The Virus then mutates and grows wings, prompting the trio to retreat to Gumball's house.
At home, the Virus mutates again and now has complete control over any type of technology, appearing on Gumball's mail account, and started to manipulate electronic objects, such as the CD player, laptop and waffle iron to attack them. The Virus then chases down and corners Gumball, Darwin and Teri with manipulated vehicles. Gumball confronts the Virus and orders him to show himself, to which the Virus obliges. The Virus goes on ranting and raving about how he is going to annihilate Gumball, only to be squashed by him.