Kraab was a veteran of the Pyros-Piscciss war, during which he suffered severe injuries, resulting in him having mechanical parts implanted in his damaged body. 95% of his body is now mechanical and 5% is Piscciss Premann.
Kraab has goldish brown-colored armor (although in Alien Force and Ultimate Alien: Cosmic Destruction it was a red and orange color), a sideways mouth, four scythe-like legs and a large, powerful pincer for a left hand. Within the pincer is a power blaster combined with a chemical sprayer. He can use his legs to burrow under the ground. When he goes underground he pulls his head down, making his neck disappear. He resembles a fiddler crab.
In Omniverse his design is slightly different, the crotch area is larger and more sphere like, and the claw arm is slightly different, he maintains the red and orange color from Alien Force.
Powers and Abilities
Kraab has a chemical spray that takes away Ghostfreak's power to become intangible and invisible, giving him the opportunity to land a blow on him. It should also be noted that Kraab talks like an actual hunter, calling Ben his "prey", and saying that he is "hardly worth the hunt". Kraab is more robotic than organic, meaning Grey Matter can deactivate him.
Kraab was one of the three bounty hunters hired by Vilgax to hunt down the Omnitrix in Hunted, the others being Sixsix and Tetrax. He was defeated when Grey Matter ripped out some wires from his neck, causing his body to go haywire.
Kraab appeared in The Final Battle: Part 1, hired by an unknown client to hunt down Ben. He was frozen by Big Chill and left aboard the ship.
Since Ben couldn't save the ship, the ship exploded, but Gwen and Kevin managed to save Kraab.