T-Pup is a remote-controlled robot built by Tails. It originally appeared in the Game Gear game Tails' Adventure as a nameless item that Tails could use to survey the territory ahead of him, but in the Sonic Universe comic books it was an essential part of the Tails' Adventure story arc.
T-Pup appears to be a robot dog that Tails created as a pet project, but became a useful tool when Tails fought against the Battle Bird Armada. It could fly, emit light from its eyes, hold items and data and even drop bombs on enemies.