Introduced in "Crabcavator", Kelper lost his shell to predators and thus took to living beneath the sea. In a bid to create a new, better shell, he began collecting Clamp pearls and melting them down for raw material. This eventually led him into conflict with Ty Rux's team of Dinotrux, who were seeking a pearl to use in repairing Click-Clack. After Ty recovered a pearl, Kelper attacked him and stole it, damaging Ty's aquatic modifications in the process.
After his gear was repaired, Ty and his friends went and confronted Kelper, and learned the full story behind his situation. As a result, they offered him a deal: they would build him a new shell in exchange for the pearl. Kelper reluctantly agreed, though he briefly attempted to renege on the deal after they were attacked by Aquadons. However, Dozer helped him to realize that he couldn't let fear rule him. The Trux succeeded in making Kelper his new shell, and he gratefully surrendered the pearl.
In "Ty vs. D-Structs", Kelper is among the many Mechazoic creatures who come to the aid of the Rengades in their final battle with D-Structs and D-Stroy. Following their victory, the large crowd eagerly anticipates helping to rebuild the Crater.