Little Yama is a robot and Mr. Yama's weapon.
During Yama's bot-fighting, he fought a robot made by a girl with pink hair, and easily defeats her with Little Yama. After that, Hiro Hamada comes over and asks if he can fight Little Yama. Hiro purposely allows his robot, Megabot, to be defeated on his first attempt. This amuses Yama and he tells Hiro to go home, but Hiro bets more money. In this second fight, Megabot wins with sudden movements and manages to cut Little Yama in half. After the fight Hiro says, "no more Little Yama", implying that Little Yama is beyond the point of repair and is permanently destroyed.