Evil Zombie Nerds

Giant Evil Zombie Nerds are the byproduct of people drinking Super-Evil Zombie Nerd Juice

Captain Underpants and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space (and the Subsequent Assault of the Equally Evil Lunchroom Zombie Nerds)
Zorx, Klax, and Jennifer infiltrate Jerome Horwitz Elementary School as lunch ladies and serve the entire school Zombie Nerd Milkshakes with the Zombie Nerd Juice. They all obeyed the aliens' command and attacked George Beard, Harold Hutchins, and Captain Underpants. The three climbed up a latter to the school roof and escaped them. After, fighting the aliens and The Dandelion of Doom, they used Anti Zombie Nerd Juice to turn everyone back to normal.

Captain Underpants: The First Epic Movie
Evil Zombie Nerds makes a brief cameo in the end credits

Known victims
Benjamin Krupp is the only known school worker who did not become a zombie.
 * Jerome Horwitz Elementary School
 * Faculty
 * Tara Ribble
 * Edith Anthrope
 * Kenny B. Meaner
 * Students
 * George Beard & Harold Hutchins (Books 9 & 10)
 * Melvin Sneedly

Appearences

 * Captain Underpants Saga
 * Captain Underpants & The Invasion Of The Incredibly Naughty Cafeteria Ladies From Outer-Space (& The Equal Assult Of The Evil, Lunch-Room Zombie Nerds
 * Captain Underpants & The Terrifying Re-Turn Of Tippy Tinkletrousers (Zombie Nerd Harold & Zombie Nerd George Only).
 * Captain Underpants & The Revolting Revenge Of The Radioactive Robo-Boxers (Still, George & Harold).