Costumes that start with M are one of the easiest letters to dress for, because the classics all live here: the mummy, the mermaid, the monster, the mobster, and the morphsuit we invented. Below we rank 20+ of the best M costumes and point each one at a complete outfit you can actually buy, rather than a list of names you then have to assemble yourself. With 71% of Americans planning to buy a costume this year and costume spending set to reach $4.3 billion, according to the National Retail Federation, the question is rarely what starts with M; it is which M costume is worth the money.
Table of Contents
- The best costumes that start with M, ranked
- Morphsuit: the M costume we invented
- Mummy and mermaid: the M classics
- Mobster, knight and mime: M costumes for men
- Monster: the carry-me photo-stealer
- Costume ideas for an M-themed party
- Easy and funny M costume ideas
- M costumes for kids
- Frequently asked questions
The best costumes that start with M, ranked
There are dozens of costume ideas beginning with M, but most fall into a handful of looks people actually search for and wear. We ranked the seven that win the room most reliably, judged on how complete each one is out of the pack, how well it photographs, and how many people it suits. Every pick below is a full MorphCostumes design, checked across 30+ measurements against our size charts, so it fits the way the picture promises rather than arriving as a bag of loose parts.
| M costume | Best for | Price | Why it makes the list |
|---|---|---|---|
| Morphsuit | Anyone, groups | $30.95 | The original all-in-one; instant, reusable, endlessly remixable |
| Mummy | Adults and kids | $35.95 | The Halloween classic, without the loose bandages that trip you up |
| Mermaid | Women | $45.95 | The go-to M look for women, in a dress you can dance in |
| Mobster | Men, groups | $50.95 | 1930s pinstripe that dresses up a whole crew at once |
| Medieval knight | Men | $30.95 | The armored-hero look without the weight of real armor |
| Monster (carry-me) | Anyone | $45.95 | Light-up eyes; the costume everyone photographs |
| Mime | Men, last-minute | $35.95 | Black-and-white and foolproof, with almost nothing to add |
Morphsuit: the M costume we invented
If you want one M costume that works for a themed party, a last-minute Halloween call and a group all at once, start with the morphsuit. It is the head-to-toe colored bodysuit we built the company on, and it is the rare costume that gets more use the more parties you go to, because a plain colored suit becomes a new character every time you add a prop.
The one-suit build
The Mens Blue Morphsuit is the original design, made from 125GSM breathable spandex you can see out of clearly but nobody can easily see into. At $30.95 it is among the cheapest complete looks on this list, and it doubles as a base layer for half the other M costumes here: add sunglasses for a secret agent, a cape for a hero, or match five friends in five colors for an instant group. Like every suit we make, it clears 500,000+ quality checks a year before it ships.
Mummy and mermaid: the M classics
Two M costumes show up every single year, for opposite reasons. The mummy is the default when someone wants classic Halloween scares; the mermaid is the default when someone wants color and glamour. Both have a DIY version that never quite works, loose bandages that unravel by the second drink, or a tail you cannot walk in, which is exactly the problem a made-for-purpose design solves.
The mummy, minus the mess
The Mummy Costume Morphsuit ($35.95) skips the bandages entirely: it is an all-over print that turns you into a gory, blood-splattered mummy on a full bodysuit, with no eyeholes to line up and no trailing strips to snag on door handles and unwind by midnight. It goes on in one step and comes off just as fast.
The mermaid you can walk in
The Womens Mermaid Costume ($45.95) is a shimmering-effect dress with a matching headband, cut so you can actually walk and dance rather than shuffle in a one-piece tail. It is a go-to M costume for women for a reason: color, shine and a silhouette that reads instantly.
Mobster, knight and mime: M costumes for men
Three of the strongest M costumes for men each solve a different night. The mobster is for when you want to look sharp and coordinate a group; the knight is for the fantasy or medieval theme; the mime is for when you left it late and need a look that assembles itself.
The mobster, for the whole crew
The Mens 30s Gangster Costume ($50.95) is a pinstripe jacket, matching pants and an attached tie: the 1930s mob look that turns a group of friends into a coordinated crew without anyone having to match a single detail. It is the most dress-up-friendly pick on this list, because a suit reads as "costume" and "smart" at the same time. For the wider era, our 1920s and 1930s gangster costume guide ranks the rest of the range.
For the other two, the Medieval Knight Costume ($30.95) is a long printed tunic carrying the graphics the crusading knights wore, lightweight enough to move and dance in with no real chainmail required, and it is one of our steadier sellers among the M looks. The Mens Mime Artist Costume ($35.95) is the last-minute hero: a full set of striped top, black trousers with braces, white gloves and a beret, finished with the black-and-white face paint you add yourself. Both link up to the full adult Halloween costumes range if none of the seven quite fit your night.
Monster: the carry-me photo-stealer
Monster is the M costume that gets the biggest reaction, and the version that lands hardest is the carry-me, the illusion costume that makes it look like a creature is hauling you around on its back. Inflatable and carry-me costumes are among our most popular in the US, because they do all the work of getting a laugh while you just stand there.
The monster that carries you
The Light Up Eye Monster Piggyback Costume ($45.95) has battery-powered glowing eyes and a stuffed pair of dangling legs, so from the front it reads as a monster giving you a lift. It is the costume people ask to photograph, and it packs down small enough to bring to a party in a bag.
Costume ideas for an M-themed party
If you are dressing for a letter party, an alphabet party or a "come as something starting with your initial" night, M gives you more range than almost any other letter. Beyond the seven ranked picks, the M list runs long: a matador, a magician, a monk, a milkmaid, a musketeer, a military officer, a motorcyclist, a monkey, a merman, and the mad scientist, which is really just a lab coat and wild hair over anything you own. Medusa works too if you want a public-domain myth with a strong silhouette, built from a green base layer and a snake headpiece.
For a group heading to the same M party, the easiest route is a shared base with individual twists: a set of colored Morphsuits reads as one crew from a distance, then each person adds their own M idea up close. That keeps the group photo coherent without forcing everyone into the same outfit, and it means one order covers most of the room.
Easy and funny M costume ideas
When you need easy, three M costumes take the least effort for the biggest return. A morphsuit is the fastest, because it is one step and no assembly. A mime is next, since the outfit is mostly a striped top plus face paint. A mummy morphsuit gets you a full Halloween look without wrapping a single bandage. For funny rather than fast, the carry-me monster and a group in clashing colored Morphsuits both get laughs on sight, and a monkey onesie is the gentle, all-ages option that always lands with kids in the room.
M costumes for kids
The M list scales down well for kids: a mummy, a mermaid, a monkey, a monster or a mini morphsuit all come in children's sizes, and they double as dress-up-day and Halloween costumes across the same fall. One practical note that outlasts the party: these are costume fabrics, so the care rule is cold hand wash and air dry, never the washing machine, which keeps the print sharp for the younger sibling who inherits it. If a size misses on the first try, returns run 30 days.
Frequently asked questions
What are some costumes that start with M?
The most popular are the mummy, the mermaid, the monster, the mobster, the medieval knight, the mime and the morphsuit. Beyond those, an M-themed party has plenty more to work with: a matador, a magician, a monk, a milkmaid, a musketeer, a military officer, a motorcyclist, a monkey and a mad scientist all start with M. Every one of the seven headline looks is a complete MorphCostumes design rather than a name you have to source piece by piece.
What is a good costume that starts with M for a themed party?
For a letter or alphabet party, a morphsuit is the safest single pick, because a colored bodysuit reads clearly from across the room and works for any age or build. If you want something with more character, the mobster suits a group, the mermaid brings color, and the carry-me monster gets the biggest laugh. For a coordinated group, put everyone in a different colored morphsuit so the crew reads as one.
What are easy costumes that start with M?
The three easiest are the morphsuit, the mime and the mummy. A morphsuit is a single step with nothing to assemble; a mime is a striped top plus face paint you likely already own; and a mummy morphsuit prints the wrapped look onto a bodysuit, so there are no bandages to wrap or lose. All three go on in seconds and come off just as fast at the end of the night.
What costume that starts with M is good for men?
The mobster is the strongest men's M costume, a 1930s pinstripe suit and hat that looks sharp and coordinates a whole group. The medieval knight is the pick for a fantasy or medieval theme, with an armored-hero look in lightweight fabric you can move in, and the mime is the reliable last-minute option. All three are full designs checked across 30+ measurements, so the fit matches the photo.
How do you care for a costume so it lasts?
Cold hand wash and air dry, never the washing machine. Costume fabrics and printed panels lose their color and shape in a hot machine cycle, while air drying keeps a morphsuit or a printed design looking new for the next party. It takes a few minutes and it is the difference between a one-night costume and one that lasts several seasons.
