Shermie the Germie is the "son" of the villain M'Lord Orus, and made his first and only appearance in the episode A Fungus Amongus. He is a purple, sapient, metal eating fungus that grew in the ship full of garbage that Orus was banished in, and came to acknowledge Orus as his father. Orus used Shermie to eat a hole through the rocket and had him aid in getting his vengeance on Atomic Betty and the Galactic Guardians.
Orus had Shermie infect Betty's ship and kidnap X-5, using him as a hostage to get them to reveal the location of Guardian headquarters. However, Betty and Sparky discovered that Sparky's Slugworm soup was the only thing capable of dissolving Shermie's fungus, and used it to combat him, Betty eventually got Shermie to swallow some, causing him to inflate to an enormous size without stopping, exploding and killing him.
Orus and what was left of Shermie that he collected were placed back on the rocket and sent back into space.