Wombat and Biker are characters from the comedic manga Nekomajin.
Wombat and Biker are first seen when they are walking through the desert and Neko Majin passes by on Biker's motorcycle. Biker screams that the bike is his; Neko Majin stops and invites them into his home. He shows them the egg where he sealed a demon named Jajan, introduces them to his pet fish Yamada Haruo, and then brings gas for Biker's motorcycle. While leaving the house, Biker touches the demon's egg and frees Jajan. Jajan attacks the two travelers, but Neko Majin saves them and seals Jajan once again.
Later, Wombat and Biker meet Neko Majin again, who is on top of an orphanage with Taiyaki. They thought Neko Majin was going to give the Taiyaki to the orphans, but Neko Majin ate all the Taiyaki and then left.