Monster by Mistake
Pizza Day
S1 E4:
Warren wakes up with a killer cold that has him sneezing and turning into the Monster every five seconds. Someone at school is sure to see him transform, so Tracy suggests he stay home. But it's Pizza Day, which means that Warren gets his favorite slice of pepperoni pizza for lunch. He doesn't want to miss that, so Johnny sticks a clothespin on Warren's nose to short circuit the sneezefest and off he goes.