The robot bulls were created by Phineas and Ferb for the robot rodeo that they made because Isabella needed a Rodeo Clown Patch. During the rodeo, Heinz turned his fog machine on, fogging up Danville and turning it into a rodeo with fog, the problems start when Buford says that a red-balloon is making the bulls angry, when a kid let it go, the bulls knock off the riders and go after the balloon, taking the rodeo as they go after it ("Robot Rodeo").
The Robot Bulls were re-built by the O.W.C.A. for stopping the Normbots with other Big Ideas, allowing Phineas and Ferb to save the Tri-State Area of Dr. Doofenshmirtz-2. (Phineas and Ferb the Movie: Across the 2nd Dimension).
|Phineas and Ferb the Movie: Across the 2nd Dimension|