The Virus is a Legendary pet in Bubble Gum Simulator. It can be obtained by opening a Hell Egg. The chance of hatching it is 0.002% (1 in 50,000), or 0.004% (1 in 25,000) with the Lucky Chancesgamepass.
It can also be obtained by purchasing the 125th slot at the Rewards Island.
A shiny version of this pet can be obtained by opening 400,000eggs and/or boxes and claiming the prize.