Chibi Kero: Kerobouru no Himitsu!?

A young Keroro attempts to impress Pururu with the Kero Ball, a device borrowed from Giroro's brother Garuru. While experimenting with its functions, he unintentionally sends four tadpoles into a pinball maze, trapping them inside. Outside, a blue tadpole named Kururu finds the ball and hears the trapped tadpoles' cries for help. He agrees to release them in exchange for a plate of curry rice. True to his word, the Kero Ball delivers the rice, but the portion keeps increasing in size. Eventually, the curry submerges Kururu, who begins to change color as the yellow sauce covers him. As the scene ends, a sinister laugh, "Kukuku," is heard.