Clown College is the seventh episode of the first season of Ben 10and the 7th episode overall.
The episode begins at a football stadium, where Max is making a barbecue while Ben and Gwen they wait for it. Then, at that moment, Max's friends arrive and they start talking, making the cousins uncomfortable by letting them escape from the place.
Already on the street, Ben and Gwen see a parade of clowns, where they find Zombozo. The clown starts talking to them, but Ben gets bored and goes with Gwen to another place.
When Ben sees some guys about to throw buckets with water to a boy who was sleeping, Ben moves away from Gwen and becomes Overflow, throwing water, but they get upset and Ben leaves. That's when Ben sees Zombozo and his henchmen planning something and decides to spy them behind a tree, but a henchman from Zombozo self-drowsy with a gas ball and goes to the tree where Ben was , causing it to also numb gas. Then the clowns go to the stadium.
In the stadium, you see Gwen, Max Tennyson and her friends watching the game, and at that moment Zombozo and his henchmen arrive in mini-cars on the court. The clowns begin to attack the public with the gas ball, causing everyone to fall hypnotized. Zombozo takes advantage of this and tells the public to throw their wallets at him.
Meanwhile, the guys that Overflow got wet, they find Ben and they come and throw him water, waking up Ben. He transforms himself into Stinkfly and flies off to the court to look for the clowns. Already on the court he faces the clowns, defeating a couple of Zombozo's henchmen. However, Zombozo shoots at the Stinkfly a sticky pink liquid preventing his flight. Then Stinkfly, before he transforms back, Gwen, Max and his friends with an odorous liquid, after this, Max and his friends come out to fight.
Surprisingly, Max and his friends are winning the clowns using only a tennis racket. When the Omnitrix is recharged, Ben transforms into Cannonbolt and defeats the Zombozo henchmen with his ability to rush, knocking down the clowns as if they were bowling pins. Now Ben and Zombozo face each other, but the latter counterattacks by throwing banana peels causing Cannonbolt to slip and crash into a wall.
Then, Zombozo prepares to launch a giant missile, while Gwen meets the trainer of Max's old team and asks for his help. He blows his whistle giving the order to the grandparents to make a giant racket with their bodies and a mesh. They hit Cannonbolt causing it to shoot at Zombozo and the missile to explode in front of him.
Later Zombozo is arrested by the police and Max celebrates victory with his friends.