Gax is a Chimera Sui Generis, a race of cephalopodic humanoids who are able to turn into giant squid-like creatures when exposed to water. Gax is essentially a clone of his DNA's donor Vilgax, but in black armor that has a white stripe on the chest. He has spikes on his knees and shoulder pads and has six tentacles dangling in the front of his face. His tentacles fades into orange and wears black wristbands. The Omnitrix symbol is on his chest. Gax first appeared in the "Omni-Tricked" four-parter, though Ben lost use of the form after an aged Vilgax retrieved his DNA sample to restore himself to his prime.
Gax resembles Vilgax, however he has black armor that has a white stripe on the chest. He has spikes on his knees and shoulder pads and has six green tentacles dangling in the front of his face. His tentacles and arms fade into brown, and he wears black, fingerless gloves. He has green sacs on the side of his head and red eyes.
Gax wears the Omnitrix symbol on his chest.
Gax is strong enough to lift the Rustbucket with relative ease.
Gax can also project powerful laser beams from his eyes.
Gax has shapeshifting arms that can change into a bunch of tentacles. These tentacles are very powerful and retain equal strength to his arms as a whole.
Gax is demonstrated to be a very skilled climber, using his sharp claws to dig into the ground.