HuntedSixsix was hired by Vilgax, alongside Kraab and Tetrax Shard, to retrieve the Omnitrix from Ben Tennyson. After they gave a demonstration of their abilities, Vilgax sent the trio to Earth where they tracked down the last location that the Omnitrix was used. Tetrax found a can with a shard from Ben’s Diamondhead form in it and Sixsix tried to take it, but Tetrax took it back. The two had a quick face-off, before Sixsix backed down and flew away to track down Ben. He found the Tennyson’s RV and cut a hole in the roof to get at Ben, but Max braked, sending Sixsix flying away. Max tried to run the bounty hunter over, but he slashed the RV’s tires, though before he could pursue the Tennysons, Kraab attacked him.
Sixsix continued to struggle with Kraab in pursuit of Ben, until they finally started to work together. They managed to capture Gwen and Max and came upon Tetrax, who was actually trying to keep the Omnitrix away from Vilgax, and Ben. Sixsix began fighting Tetrax, eventually gaining the upperhand and noticed Grey Matter taking down Kraab. He tried to fire at him, but Max leapt on the bounty hunter’s back and Sixsix threw him off, before trying to cut him in half with an energy buzz saw. However Grey Matter leapt on him and pulled the nerve clusters in Sixsix’s armor, making him go haywire. The bounty hunter’s jetpack went off, sending him crashing through a water tower, before he and Kraab were crushed by it.
The Galactic EnforcersSixsix was later hired along with Vulkanus to steal the ingredients for a bomb powerful enough to destroy an entire solar system. They first stole Element X, before heading to Earth to obtain Bicenthium alloy (iron ore, which is actually quite rare in the rest of the universe). Upon landing on Earth, Sixsix and Vulkanus had an encounter with Ben and Sixsix managed to shock and disable his body functions before preparing to launch his missiles at him. However the Galactic Enforcers arrived and managed to fight the two bounty hunters, forcing Sixsix to use a flash capsule to retreat. The pair headed to a nearby iron mine, seeking iron ore when the Galactic Enforcers arrived, though without their leader, Ultimos, who was weakened from the chocolate Ben gave him. This time, Sixsix and Vulkanus managed to defeat them and Ben and the two bounty hunters left with their iron ore after Sixsix started a rockslide to distract the heroes. They headed to a steel mill where Vulkanus began looked for a pure iron mixture, but the Galactic Enforcers and Ben arrived. Eventually, Sixsix and Vulkanus got liquid metal dropped onto them and cooled, trapping them.
Secret of the OmnitrixSixsix ended up in Incarcecon and eventually Tetrax, Ben, and Gwen found their way to Incarcecon looking for Azmuth so as to deactivate the Omnitrix’s self-destruct countdown. Sixsix recognized Tetrax and attacked him, blaming him for his imprisonment in Incarcecon. They began fighting and Tetrax managed to knock Sixsix out, but he slipped away when the Petrosapien was distracted. When Tetrax escaped Incarcecon with the Tennysons and Myaxx, Sixsix managed to cling to his ship and escape. However he was blasted off by a security drone and ended up floating in space, where he was found by Vilgax, who was pursuing the Omnitrix. Vilgax picked up Sixsix, who told him what had happened and aided in attacking Tetrax’s ship.
He and Vilgax headed to the cockpit, before Sixsix was ordered to stop Tetrax and Myaxx, who were attempting to free their ship from Vilgax’s tethers.
Sixsix engaged Tetrax, but was blasted by Ben in the gyropod, breaking his helmet and sending him flying into space. However Vilgax recovered him and they arrived on Xenon where Azmuth was, attacking his home with rest of Vilgax’s forces. In the battle, Sixsix again went after Tetrax until he was knocked out and finally defeated by the Petrosapien.
OmniverseSixsix returned in Vilgax Must Croak where he, Sevenseven, and Eighteight were hired by Attea to kill Vilgax, but his plans fail when Ben, Rook and a group of Plumbers prevent it, and Vilgax escaped.
In Cough It Up, Sixsix, together with his siblings, were hired by Psyphon to get him a precious item, but they are defeated by Ben, Rook and Spanner.
He makes his first appearance in the second part of Omni-Tricked where, next to Kraab, he breaks the roof of the car where Phil and Ben were. After Tetrax locked Phil in the cockpit, he shoots a net at Ben catching him and then tries to grab him next to Kraab and Tetrax. Ben becomes Overflow and with his teammates, Sixsix makes an attempt to ram him but the above-mentioned alien attacks him with water jets. Tetrax shoots Overflow but it dodges the shot and this causes the door of the next car to break causing everyone to be taken to the other car. There after Ben transforms into XLR8 and fights with Tetrax, he tries to shoot him but XLR8 dodges the shot and it attacks Tetrax. Later escapes with Tetrax and Kraab in a portal created by the latter.
He returns in the third part of the episode seconds after Vil absorbed Gax through a portal along with Kraab and Sixsix where instead of attacking Ben, they attack Vilgax demonstrating that from the beginning he was his target.
After Kraab shot Vilgax, Sixsix is the first to attack him. He flies until he is behind him and grabs him with his whips but Vilgax grabs them and revokes Sixsix by throwing him against a tree. Sixsix uses this as an impulse and attacks Vilgax, being backed by Tetrax who helps him by creating walls of Tadenita. But being less in power, Vilgax manages to defeat him and launch him to the portal from which he came along with his teammates.
In Bounty Ball, He came through a portal along with Kraab and Tetrax fighting Ben again and attempting to take the Omnitrix, but Sixsix went back into the portal when Shock Rock defeated him.
Sixsix’s armor contains a huge arsenal of weapons and devices, including hand-held laser blasters, missiles, mounted laser blasters on his back, grenades, a jetpack, an energy sword, and buzz saws. Sixsix also has small extra arms that can use his other weapons when he’s holding his blasters and a radar that can track the Omnitirx when it is used. Sixsix can also apparently survive in space.
- Sixsix has an older brother named Sevenseven.
- He also has two sisters named Eighteight and Twotwo.
- He is the only member of his race seen without his armor but it has been stated he is mutated so it is unknown what normal Sotoraggians look like.
- Sixsix speaks in an alien language (most likely that of the Sotoraggians’ since Sevenseven speaks it) but can understand English and others can understand him.
- Nobody voices Sixsix in Omniverse.
- Sixsix's armor is built from the shell of an assassin robot that he "gutted".
- The rivalry between Tetrax and Sixsix goes on well into the future until it is settled in one final showdown.