In "Kixx", a group of boxers were seen working out at the beach gym when Experiment 601 (Kixx) suddenly attacked the beach and defeated all the boxers with ease. Stitch then arrived for a battle rematch with Kixx, since the latter had easily defeated Stitch once before. At first, 601 was able to easily overpower Stitch. However, with Lilo's training which included using a special book entitled Fighting Four-Armed Monsters, Stitch was able to block and counter all of Kixx's blows easily. Stitch then used all the tactics that Lilo taught him (as well as stuff around the beach gym) and eventually defeated Kixx by restraining him with the ropes from the boxing posts. After Kixx was rehabilitated, he was found a one true place teaching people kickboxing while hosting his own workout video, as Stitch pointed out to Lilo that teaching is good.
In "Angel", Kixx was seen hanging out at the beach gym. Angel then arrived at the gym and reverted Kixx back to evil by singing her siren song. Later, when Stitch arrived at the gym, Kixx suddenly attacked Stitch, much to the latter's confusion. Stitch was then forced to battle Kixx again and incapacitate him.