Speed Demon is a mutant muscle car that turns whoever drives him into a mutant driver that is thirsty for high speed.
At the end of the episode, The Croaking, we see a purple muscle car passing through the Punk Frogs' sacred Mutagen that Rasputin the Mad Frog had lost during the Punk Frog's fight with the Turtles spilled on the road.
In Race with the Demon, it pursues Donatello, April O'Neil, and Casey Jones in their station wagon and tries to run them off the road. News of the Demon Racer's vehicle causing trouble on the road reaches the local news. In order to get even with the Speed Demon, Casey and Donatello construct a racing vehicle to compete with him. Casey later encounters the Speed Demon's vehicle where he finds that Speed Demon is actually a mutant. When Speed Demon plans to run an old lady and her vehicle off the road, Casey repelled the Speed Demon just as the Ninja Turtles catch up. Michelangelo found Mutagen on the road that leaked from the Speed Demon as Donatello claims a sample of it. While piloting the new car (which was made from parts of Kraang technology) with Dr. Cluckingsworth, Casey works to take down Speed Demon by useing a smokescreen to slow it down. Donatello removed the driver from the car, who restores to normal. Donatello unfortunately learns too late that the car is the actual mutant as Speed Demon eats him, which results in the creature possessing the mutant turtle's body. In order to get Donatello out of Speed Demon, Casey ends up in a race to Dead Man's Curb for the fate of Donatello. With help from Dr. Cluckingsworth, Casey frees Donatello from Speed Demon as it starts to attack them. After the other Turtles arrive and run Speed Demon off a cliff, he vows to return before exploding. However, in Eyes of the Chimera, it's revealed that the explosion released Mutagen that ended up creating the Chimera.
Method of ConsumptionEdit
The Speed Demon consumes its victims by using the hood of the vehicle as its mouth. Once a human or mutant is eaten, the Speed-Demon will posses its body, allowing to become more powerful than before.