Cannonbolt

Cannonbolt (voiced by Fred Tatasciore on Ben and Vanessa Marshall on Gwen in the first series and Dee Bradley Baker in the second series) is an Arburian Pelarota (based on pelota, Spanish for "ball" and rota, a play on "rotation") from the planet Arburia. The information from the Bandai Alien Collection toy for Cannonbolt refers to his species as a Vulpinic Tortugan (tortuga is Spanish for "turtle") from the planet Vulpin, which Wildmutt also originates from. The Vulpinic Tortugans are Pellorotors that moved to Vulpin, then mutated due to the pollution and developed the ability to breath fire. The Pellorotor home planet was destroyed by "The Great One" shortly before Ben discovers the form in "The Big Tick".

Cannonbolt is the first new alien to appear on the Omnitrix, and eventually replaces Ghostfreak in the opening theme. Cannonbolt was originally meant to be one of the original ten aliens, but was replaced by Diamondhead in production. Cannonbolt is a hulking, broad-shouldered alien covered in natural armor plating. This armor can resist almost any attack, ranging from acids to lasers to extreme heat. By curling up into a ball, much like an armadillo or pillbug, Cannonbolt can encase himself in his armor, becoming virtually invulnerable. On Cannonbolt's planet curling up into a ball is a defence mechanism. He can then spin himself like a wheel, rolling into enemies at high speeds to attack. The drawback is that Cannonbolt quickly picks up inertia, which can make hitting more maneuverable targets difficult, as he can't slow down quickly. In addition, Cannonbolt's speed and maneuverability is limited outside of his ball form, owing to his bulk and high center of gravity.

Cannonbolt makes an appearance in the second season finale of Ben 10: Alien Force after Azmuth unlocks the Omnitrix master control. His appearance is the same as in the original series, with the exception of Omnitrix symbol, which has been moved to his chest, his eyes now being green instead of yellow, the lower black stripe being gone, and has a hint of orange in his shells. In the third season, he becomes one of Ben's regularly used aliens.