CANNONBOLT

Cannonbolt (voiced by Fred Tatasciore) 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 Pelarotan 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 an invulnerable ball. He can then spin himself like a wheel, rolling into enemies at high speeds to attack. The drawback is that Cannonbolt has trouble slowing down once he gets going, which can make hitting more maneuverable targets difficult. In addition, Cannonbolt's speed and maneuverability is limited outside of his ball form, owing to his bulk and high center of gravity.