When Dust Brain uses his bandages to cover Colonel Corn's mouth and prevent him from telling any more corny puns to weaken the Madballs, Colonel Corn pushes a button that summons a Cornball. The Cornball also tells bad jokes and weakens Dust Brain enough to let go of Colonel Corn. The Cornball was defeated when Lynn pretended to insult the Madballs, angering Screamin' Meemie. Screamin' Meemie's anger made him glow white-hot, causing the Cornball to pop and turn into pop corn. The heat also popped off the corn from Colonel Corn's body, making him weak enough to be turned over to the police.
Like Colonel Corn, the Cornball was able to tell terrible jokes capable of weakening the Madballs.