Phantom Virus

The Phantom Virus is a menacing virtual virus ghost and the main antagonist in "Scooby-Doo and the Cyber Chase".

During the final level which is in a carnival, the Virus assembles Creeper, Jaguaro, Gator Ghoul, Tar Monster, and Old Ironface (old enemies from Mystery Inc.'s past) to destroy the Mystery gang until the Virus is destroyed when Scooby grabs the last box of Scooby Snacks, along with the monsters he assembled.

It was revealed by clues left by the virus that a student at a university named Bill McLemore made the virus because his baseball video game project was not picked by Professor Kaufman, so he exacted revenge on the Professor and his assistant Eric Staufer (who's video game design was chosen) by creating the Phantom Virus. Bill ends up getting foiled and arrested. Whether the virus did this out of betrayal or programming is unknown.