M-O (Microbe-Obliterator) is a robot aboard the Axiom programmed to clean items deemed contaminated. He travels around on a single roller, equipped with cleaning tools. M-O befriends WALL-E after he attempts to clean the dirty robot, following him all over the ship. His timely arrival in the garbage disposal area proves significant when he unintentionally becomes a wedge between doors, preventing WALL•E and EVE from being sucked out the airlock. He then fully cleans WALL•E and accompanies him and EVE into bringing the plant to the holodetector on the libo deck so the Axiom can jump to Earth. When they arrive back on Earth, M-O ushers the other robots into giving WALL•E and EVE some privacy as they share a tender moment.