Bob is a robot created by Dr. Zimmer. He appeared in Arthur's fantasy in "What is that Thing?". Arthur thought that the bobbin could be a robot's brain. Bob was playing tic-tac-toe with Dr. Zimmer when it was his move. Bob splatted his chocolate ice cream cone on his head, and Dr. Zimmer realized something was wrong. He is identical in appearance to the Army of Robots from "Arthur Accused!".