Millipedes (class Diplopoda) are myriapodous arthropods that have two pairs of legs on most body segments. Each double-legged segment is a result of two single segments fused together as one (the name "Diplopoda" comes from the Greek words διπλοῦς (diplous), "double" and ποδός (podos), "foot"). Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a ball, like a pillbug. The name "millipede" is a compound word formed from the Latin roots mille ("thousand") and pes ("foot"). Despite their name, no known millipede has 1,000 legs, although the rare species Illacme plenipes has up to 750. Common species have between 36 and 400 legs. There are approximately 12,000 named species in ca. 140 families. The longest species is the giant African millipede (Archispirostreptus gigas). Most millipedes are slow-moving detritivores, eating decaying leaves and other dead plant matter. However, they can also be minor garden pests, especially in greenhouses where they can cause severe damage to emergent seedlings. Millipedes can be easily distinguished from the somewhat similar and related centipedes (Class Chilopoda) which move rapidly, are carnivorous, and have a single pair of legs for each body segment. The scientific study of millipedes is known as diplopodology, and a scientist who studies them is called a diplopodologist.

Mission Cobra (響尾蛇 Rattlesnake), released in Australia as Sidewinder, is a 1989 action arcade game developed by Sachen and published by HES Interactive. It was later published in the US as Mission Cobra by Bunch Games.

Mission: Impossible is an American television series that was created and initially produced by Bruce Geller. It chronicles the missions of a team of secret government agents known as the Impossible Missions Force (IMF). In the first season, the team is led by Dan Briggs, played by Steven Hill; Jim Phelps, played by Peter Graves, takes charge for the remaining seasons. A hallmark of the series shows Briggs or Phelps receiving his instructions on a recording that then self-destructs, followed by the theme music composed by Lalo Schifrin. The series aired on the CBS network from September 1966 to March 1973, then returned to television for two seasons on ABC, from 1988 to 1990, retaining only Graves in the cast. It later inspired a popular series of theatrical motion pictures starring Tom Cruise, beginning in 1996.

Mitsume ga Tooru (三つ目がとおる, Mitsume ga tōru, "The Three-eyed One") is a video game for the Family Computer that was developed by Natsume and published by Tomy. It is based on the manga and anime called The Three-Eyed One. The main character is Hosuke Sharaku. There is also a Mitsume ga Tooru game for the original MSX called Mitsume ga Tooru: The Three-Eyed One Comes Here, which was released by Natsume two years before this one.