O-3 is a robot character from the anime Time Bokan: The Villains Strike Back. He serves as the new robot companion of Tokio and Karen, the young heroes of the series, and he replaces Pikobo, the robot who had previously accompanied the pair. His full designation is OTNP55 Etcetra Etcetra Etcetra Deluxe 3, and the name O-3 by which he is known is a shortened form of that model designation. Within the story, O-3 fulfills a supporting role, joining Tokio and Karen as a mechanical partner and assisting them in their activities, so his function in the cast is defined by his relationship to the two human protagonists rather than by a story arc of his own. His introduction marks a change in the setup of the hero team for this installment of the franchise, as he takes over the companion role held by his predecessor.