Whenever Ben needs to smash, throw or beat something up, Fourarms is the hero of choice.Standing twelve feet tall, this formidable four-armed Ben 10 alien uses his strength to dish out punishment, while his tough skin protects him from harm.
Ben Tennyson might seem like an ordinary 10-year-old boy — he plays video games, rides his bike and is a bit of a trouble maker - but thanks to his Omnitrix watch, he also has the ability to change into 10 different alien heroes.
Diamondhead is a crystalline alien whose body is harder than diamond.
Out of all the Ben 10 aliens he's the most invulnerable to physical attacks, and can cut and slash through almost anything.
He can also use his body to reflect light and beam-based weapons.
The aquatic hero of the Ben 10 aliens, Ripjaws is an extraordinary swimmer.
He can breathe underwater and change his legs into a large tail with fins, which means he's remarkably fast in the water.
He can also unhinge his powerful jaws to deliver a devastating bite.
At a tiny five inches tall, Grey Matter is part of an frog-like alien race bred to enter complex machines and repair them from the inside.
He gives Ben a temporary boost in intelligence when transformed, and his slimy skin makes him the hardest to catch out of all of the Ben 10 aliens.