Monsters, Inc. is one of the friendliest themes I know for a costume build, because every character is basically a block of colour with one signature detail: Sulley’s blue fur and purple spots, Mike’s single eye on a green body, Boo’s pink nightshirt, Celia’s snake hair and the CDA team’s yellow suits. That means most of these start from plain clothes you already own, with felt and craft foam doing the character work. Below are 30 ideas, from solo characters to couples, families, office groups and two object costumes based on a scream canister and Boo’s door. I’ve noted where a build gets fiddly and where the quick shortcut is honestly fine.
Felt Spots, Fur and the Glue That Actually Holds
Almost every costume below comes down to sticking felt shapes onto a base garment, and how you attach them decides whether they’re still there at the end of the night. The base fabric matters as much as the adhesive.
- Hot glue grips felt to felt well, but on stretchy fleece or jersey it cracks the moment the fabric stretches, and it turns brittle in cold air. I only use it on rigid pieces like headbands and cardboard props.
- Flexible fabric glue soaks into both layers and bends with the garment. It needs hours to cure, so do the spots the day before, laid flat with a sheet of card inside the garment so the front doesn’t glue to the back.
- Fusible web ironed between felt and cotton is quick and neat, but faux fur and fleece can melt or flatten under an iron, so test on a hidden seam allowance first.
- Stitching is the only method I trust on elbows, knees and seats. A few loose running stitches round the edge of each spot take minutes and survive a night of sitting and crawling.
On faux fur, part the pile with your fingers before gluing so the felt meets the knitted backing rather than the tips of the fur. Glue that only catches the tips peels away with the strands as soon as someone brushes past.
1. Sulley Costume With Blue Fur
Sulley lives or dies on the spots. I cut them freehand from purple felt in uneven blobs of different sizes and scatter them across the back, sleeves and legs, because a neat repeating pattern reads as polka dots rather than fur. A fuzzy turquoise jumpsuit is the easiest base, though a blue hoodie with joggers works too; on fleece, glued felt tends to peel at the elbows, so I add a few running stitches to anything on a sleeve. The headband needs small beige horns and rounded blue ears, and a little blue at the temples with purple eyeshadow is all the makeup he needs. Furry shoe covers or turquoise sneakers finish him, and a clipboard or small door prop puts him in the factory.
2. Mike Wazowski Costume With Green T-Shirt
Mike is a one-detail costume, so the eye has to be right. I build it in three layers of felt (white, then blue, then a black pupil) and make it bigger than feels sensible, close to the width of the chest, because a small eye just looks like a logo on a green T-shirt. Green leggings or joggers keep the colour unbroken, two small gray horns go on a headband, and a green beanie smooths the head into his round shape. For the face, green eyeshadow and a thin blue ring around one eye is enough. Green sneakers and a toy microphone or comedy cue cards suit his patter.
3. Boo Pink Pajama Costume
Boo is the costume I point people to when they have one evening and no sewing machine. An oversized coral-pink T-shirt over lavender leggings with white socks is the whole outfit; add white sneakers if it’s going outside. The hair matters more than you’d think: two small pigtails, set high and a little uneven, in colourful round hair ties. Keep makeup to rosy cheeks and maybe a soft pink lip. Adults can carry a small plush monster, and kids usually like a treat bucket decorated as a bedroom door. It stays comfortable through a long walk or a whole school day.
4. Boo Monster Disguise Costume
This is Boo in the purple monster disguise Mike and Sulley put her in, and it’s a genuine sewing project. I start with a padded purple tunic to the knees, then add lavender scales or rounded felt panels down the sides. The hood carries the character: two long eye stalks with big white craft eyes, plus mop-like strands for hair. Stalks that are only lightly stuffed flop forward, so I stuff them firmly and slide a strip of craft foam inside each one. Cut the armholes generously, because a child will want to lift their arms for everything. Purple leggings and matching sneakers go underneath, hair tucks inside the hood, and makeup can stay minimal since the hood frames the face.
5. Celia Mae Costume With Snake Hair
Celia’s hair is the hard part and the part everyone looks at. I’d use a violet wig and pin on several soft stuffed snakes or foam curls; heavy toy snakes drag a wig forward and give you a headache within the hour. Her single large eye sits in the middle of the forehead, and a craft eye stays put with skin-safe adhesive, but patch-test it on the inside of your wrist the day before. A fitted mint-green dress with a faint scale texture, matching green tights and green ankle boots suggest her tentacled lower half without hobbling you. Lavender eyeshadow, pink lipstick and a fuzzy pink cardigan or neck trim finish her, with a small heart-shaped bag to carry.
6. Roz Costume With Red Sweater
Roz is my pick for anyone who has to wear a costume at a desk. A fitted red sweater over a mustard-yellow skirt, a pointed white collar, dark cat-eye glasses and an ID badge get you most of the way. The head is where people overdo it: a pale yellow knit cap for her rounded shape and a small tuft of gray yarn stitched to the top is plenty. Muted yellow on the forehead and cheeks, thin arched brows and a neutral lip give her that unimpressed look without a mask. Mustard tights and brown loafers keep it practical, and a clipboard of generic paperwork with a pencil on a chain is the detail people tend to spot first.
7. Randall Boggs Costume With Purple Scales
Randall needs to look sleek, so I avoid anything fuzzy here. A violet bodysuit is the cleanest base, with blue felt spots and a pale aqua panel down the stomach; a fitted long-sleeve top with purple pants works if you can’t find one. His extra limbs are the fun bit. Fabric-covered foam tubes tied at the waist suggest them, and I keep them hanging no lower than mid-thigh so they don’t catch between your knees as you walk. Add three soft blue fins on a purple headband, slick the hair back, and use lavender face makeup with narrow blue eye accents. Purple sneakers with blue laces and a rolled scare-floor blueprint keep him sly rather than threatening.
8. Henry Waternoose Costume With Red Vest
Waternoose is the most theatrical build in the list, and the tailoring does half the job. Layer a crisp white shirt, a burgundy vest and a black jacket with a coordinating tie over gray trousers, then buckle on a padded belt and hang several stuffed gray fabric legs from it for his crab-like body. I sew those legs from stretch knit and stuff them loosely, because firm stuffing turns them into stiff sticks that swing into everyone around you. A pale gray bald cap or close hood with small ears, soft gray face makeup, bushy brows and round glasses finish the head. Black dress shoes, an executive badge and a folder of generic energy reports, with the extra legs kept short enough that you can’t step on them.
9. CDA Agent Costume With Yellow Suit
CDA agents are the easiest way to add numbers to a group, since the uniform is identical and anyone can wear it. Start with a loose yellow coverall, or a yellow jacket and pants if you can’t find one, then add black gloves, a wide utility belt and black rain boots. A clear face shield attached to a yellow hood reads as protective gear without hiding your face, though I’d check you can still see your feet through it before going near stairs. Hair goes under the hood and makeup stays natural. A chest badge with block letters, a painted cardboard and craft-foam scanner, and black tubing running to a small backpack finish the kit. A few strips of reflective tape look like suit detail and make you easier for drivers to see after dark.
10. George Sanderson Costume With White Sock
George only works if people get the joke, so the sock and the number come first. Fix a clean white costume sock to the middle of the back with a safety pin or a hook-and-loop dot, so it comes off when you sit down, and carry a light sign reading “2319” in big numbers. The rest is an orange furry hoodie or jumpsuit with red or rust felt spots, a horned orange hood with rounded ears, and furry covers over supportive sneakers. Orange face makeup with darker spots on the cheeks keeps it quick. He’s much funnier with a partner, so put a second person in a yellow CDA suit with a cardboard scanner.
11. Fungus Costume With Red Glasses
With Fungus, the glasses are the thing to spend effort on. Find large round frames in blue or purple; toy frames with no lenses are even better because they won’t fog up in a warm room. The body is a red hoodie and matching pants with round purple felt patches, plus a soft padded stomach panel. Keep that padding thin, or you’ll be too warm indoors within an hour. A red beanie with small fabric horns and side ears covers the head, and coral face paint with darker red freckles does the rest. Purple sneakers and a clipboard or headset make him the nervous assistant, and he pairs naturally with a purple Randall.
12. Yeti Costume With Snow Cone Prop
The Yeti is the warmest costume here, which makes it the one I’d suggest for an outdoor night. A fluffy white jacket with faux-fur pants is the cosy version, and white leg warmers over loose sweatpants get a similar effect for less. A white hood with rounded ears and a pale-blue face opening, plus long shaggy white hair from a wig or yarn stitched round the hood, give him his shape. White fur sheds onto anything dark, so lint-roll before you leave and stay off black sofas. Icy blue eyeshadow, rosy cheeks, white furry boot covers over nonslip shoes and a paper-cup snow cone stuffed with tissue paper finish him, with a light blue scarf for warmth that stays on theme.
13. Smitty And Needleman Duo Costume
Smitty and Needleman are a good deep cut for two friends who don’t want to be Mike and Sulley. One wears a light blue furry jumpsuit with a tall flexible horn, the other a yellow-green monster tunic covered in soft eye details. Matching gloves, colourful hoods and makeup in each costume’s main shade tie them together, with faux-fur gaiters over comfortable sneakers. A cardboard door-shredder control panel carried between you makes a nice shared prop, and employee badges help people place you. I make tall horns and eye stalks from foam rather than hard plastic, because in a crowded room they will end up near someone’s face.
14. Scare Floor Worker Costume
This is the one to choose if you’d rather invent a monster than copy one. The uniform is plain work clothing: navy cargo pants, a blue work shirt and a bright vest with a homemade employee badge. The monster lives on your head, as a headband with soft horns, fuzzy ears or flexible eye stalks in colours you pick yourself. Repeat those exact colours in the makeup on the eyelids, cheek spots and brows, so the whole thing reads as one creature rather than a worker in a novelty headband. Sturdy sneakers or work boots handle the standing, and a clipboard of made-up scare totals sells it. It suits any body and any gender, and a group can share the uniform while each person designs their own monster.
15. Mike And Sulley Couple Costume
Mike and Sulley work as a pair because they contrast so clearly: small and green next to big and blue. The Mike wearer goes in lime green with the big felt eye, small horns, green face accents and matching sneakers, while Sulley gets a turquoise furry jacket, blue pants, purple spots, horned ears and blue shoe covers. Coordinating beanies or hoods keep both heads simple. For an indoor party I’d swap thick costume fur for lightweight fleece, because fur jackets get uncomfortably hot once a room fills up. Give Mike a toy microphone and Sulley a small door prop, then stand side by side for photos so the green and blue land together.
16. Sulley And Boo Duo Costume
This duo has a built-in effort split, which is why it suits a parent and child or two friends where only one wants to dress up properly. Sulley gets the turquoise hoodie and joggers with purple felt spots, a horned headband, blue makeup and furry shoe covers. Boo is an oversized coral-pink T-shirt, lavender leggings, white socks and sneakers, with two short pigtails in bright ties and soft rosy cheeks. Sulley carries a light section of flower-covered door and Boo holds a small plush. If Boo is a toddler, make the door entirely Sulley’s job, since little arms tire of carrying anything very quickly.
17. Mike And Celia Couple Costume
Mike and Celia are the romantic version, and their shared green tones do the coordinating for you. Mike wears a lime-green round tunic, or a shirt and pants, with one oversized eye, two small horns, green makeup and green sneakers. Celia wears a mint scale-print dress with green tights, ankle boots, lavender eye makeup and a purple snake wig, plus a fuzzy pink collar or cropped cardigan. Use foam snakes on that wig rather than fabric ones packed with filling, so it stays put through a night of dancing. He carries a toy microphone, she carries a heart-shaped bag, and the very different silhouettes keep each character clear.
18. Randall And Fungus Duo Costume
Randall and Fungus are a villain-and-assistant pair with nothing frightening in them, so they sit well at family parties. Randall is purple clothing with blue spots, a pale stomach panel, soft limbs at the waist, slicked hair or a hood, lavender makeup and purple sneakers. Fungus is a coral-red tracksuit with purple spots, a padded belly, round blue glasses, a small horned beanie and red slip-ons, and matching employee badges link the two. Build every added piece from fleece and felt, since foam and fur on both costumes gets bulky fast in a car. They’re at their best when you play it up: Randall scheming, Fungus fretting over his clipboard.
19. Monsters Inc Family Of Three Costume
For three, Sulley, Mike and Boo is the obvious set, and it’s obvious for a reason: two bold adult shapes and one small pink one. One adult wears a blue furry Sulley hoodie with purple-spotted pants, horns, blue makeup and turquoise sneakers. The other wears a green Mike shirt with one large eye, green pants, small horns and matching shoes. The child or baby is Boo in a pink T-shirt dress, lavender leggings, white socks and soft shoes, with two pigtails or a pigtail headband if their hair is short. One light flower-covered door is the shared prop. Make both adult costumes loose enough to go over warm layers, because trick-or-treating means a lot of standing in doorways.
20. Monsters Inc Family Of Four Costume
Four lets you add Roz, which is handy if one adult would rather wear real clothes. Sulley gets blue faux fur, purple spots, horns and furry shoe covers; Mike gets lime-green separates, a giant felt eye, a green cap and matching sneakers; Boo wears pink sleepwear, lavender leggings, white shoes and two small pigtails. Roz is a red sweater and mustard skirt with a gray hair tuft, pointed glasses, brown loafers and a clipboard. Keep everyone’s makeup simple and in their own colour, and let a shared cardboard door or scream canister pull the photos together. Only Sulley is properly warm here, so I’d hand the fur to whoever feels the cold most.
21. Monsters Inc Group Costume
A big group can stretch to Sulley, Mike, Boo, Celia, Roz, Randall, George and a few CDA agents. My one rule for groups is that every person sorts their colour base, their headpiece and walkable shoes before anyone starts on props. Sulley is blue fur and purple spots, Mike is green with one large eye, Boo is pink and lavender, Celia is mint and purple, Roz is red and mustard, Randall is spotted violet, George is orange with a white sock, and the CDA agents are yellow coveralls with black kit. Matching employee badges across everyone make it one crew. Share the bigger props, such as the flower door and the cardboard scanner, instead of handing everyone something bulky to carry.
22. Scream Canister Costume
A scream canister is a body cylinder, and the real decision is the material. I’d curl a sheet of lightweight foam or thin cardboard into a tube and bind the cut edges and armholes in soft fabric so they don’t scratch your arms. Black-and-yellow striped tape near the top and bottom and a round gauge of painted craft foam make it read from across a room. Padded shoulder straps inside carry the weight, and the lower edge should sit above your knees or you’ll be shuffling all night. Underneath, a yellow long-sleeve top and leggings, hair in a high ponytail or a silver beanie, silver eyeliner with yellow accents, and gray sneakers. Expect to stand most of the evening, because sitting in a cylinder is awkward.
23. Boo Door Costume
Boo’s door is the prop people recognise most, so it makes a good wearable. Cut it from lightweight cardboard, or from corrugated plastic if there’s any chance of rain, since cardboard goes soft and bends once it gets damp. Paint it white with pale pink flowers and hang it on fabric shoulder straps over the front or back of the body. Underneath, a pale pink top with white pants and pink sneakers keeps the palette, with flower clips in the hair and soft pink eyeshadow. Carry a big craft key or a plush monster. Round every corner and keep the panel narrow enough to turn through doorways and crowds without clipping anyone.
24. Roz Office Costume
This is the Roz I’d wear to work, because it’s really just office clothes with intent. A rust-red cardigan, mustard midi skirt, cream collared blouse and opaque yellow tights, with brown loafers or low ankle boots for a full day on your feet. For the hair, a short gray wig with one pointed section on top, or a temporary gray streak sprayed into your own hair. Temporary colour spray rubs off onto collars, so let it dry fully before the cream blouse goes anywhere near it. Angular glasses, muted yellow eyeshadow, sharp brows and a neutral lip, plus an employee badge, pencil chain and clipboard of generic paperwork. It gives the character away without a bodysuit, which is why it suits teachers and receptionists who still have a job to do.
25. Easy Mike Wazowski Hoodie Costume
When time is short, a green hoodie and matching sweatpants become Mike in an evening. Cut the eye from white, blue and black felt, then fix it with fabric tape or safety pins from the inside so the hoodie comes back undamaged after Halloween. Two small horns of stuffed gray felt go on the hood, and hair tucks inside or under a lime-green beanie. Green eyeshadow around one eye and a neat blue circle under the lower lash line, white or green sneakers and a toy microphone are the rest. There’s no sewing at all, and it’s comfortable enough for a school event or a long night on the porch handing out candy.
26. Glam Sulley Costume With Tulle Skirt
If a jumpsuit isn’t your thing, this version keeps Sulley’s colours and turns them into a party outfit. A turquoise faux-fur jacket goes over a layered blue tulle skirt, both with purple felt spots, plus opaque blue tights and a fitted turquoise top so the volume stays balanced. Glue won’t hold felt to tulle, so I stitch the skirt spots by hand through two or three layers of net. Blue ankle boots or platform sneakers, hair in big waves or a turquoise wig if you want the full colour, and a horned ear headband. Shimmery blue eyeshadow, purple liner and a cool highlighter suit it, with a small bag decorated as a factory door.
27. Plus Size Mike Wazowski Costume
For a plus size Mike, I’d skip the rigid round tunic and work with soft layers that move with you. A lime-green swing dress or sweatshirt dress is the easiest base, though a relaxed T-shirt over green leggings works too. Place the big felt eye in the centre and check it lies flat when you sit, since stiff felt can buckle across a curve and dig in; a softer felt or a fabric eye backed with light interfacing solves that. Add a curved black felt smile, a headband with two light horns, and natural hair or a green head wrap. Green eyeshadow, blue liner and a bright pink lip, with supportive green sneakers and a toy microphone, mean you can sit, dance and walk all evening without fiddling with anything.
28. Maternity Mike Wazowski Costume
Mike’s round body suits a bump so well that this costume almost designs itself. Wear a stretchy lime-green maternity dress or long green top with soft leggings, and set the big felt eye over the belly. I’d sew the eye onto a separate green belly band rather than glue it to the dress, because a bump changes shape from week to week and a band can be moved. A curved smile goes below it and two small horns sit on a light headband, with hair in a ponytail or braid. Green eyeshadow and blue liner are plenty. Choose supportive green sneakers over heels, carry a toy microphone, and add a green cardigan for warmth that still leaves the eye showing.
29. Baby Boo Costume
For a baby Boo, soft and simple is the whole brief, with nothing loose a baby could pull off and put in their mouth. A long-sleeve pink bodysuit or cotton dress, lavender leggings and white socks are enough. Soft crib shoes only if you need them; hard soles don’t belong on a baby who isn’t walking yet. A soft headband with two tiny fabric pigtails suggests her hair without tugging at fine baby hair. Skip face makeup entirely, because the pink-and-purple clothes carry the character on their own. A small plush monster is fine for supervised photos but shouldn’t be left in a crib or stroller, and with the parents as Sulley and Mike the baby becomes the centre of the set.
30. Pet Sulley Costume
A pet Sulley should be a light cover over a harness, never a full furry suit, because animals overheat quickly under fur. Stitch soft purple felt spots onto breathable turquoise fabric and secure it over your pet’s own harness so nothing pulls at their legs. A loose hood with small fabric horns is only worth trying if your pet already tolerates headwear. Never cover the eyes, ears, mouth, paws or tail, and skip makeup and coloured sprays entirely. A turquoise leash and a small removable badge are plenty, with booties only for pets already used to them. Introduce each piece slowly, stay with your pet the whole time, and take it off at the first sign of discomfort or heavy panting.
Horns, Ears and Eye Stalks That Stay Upright
Most of these looks put the character on your head, and a headpiece that flops halfway through the evening undoes the whole costume. Three habits keep mine standing.
Start With a Wide Headband
A thin plastic band pinches behind the ears before long. A wider padded band, or a plain one wrapped in a strip of felt, spreads the pressure and gives the horns more surface to anchor to.
Stuff Firmly, Then Add a Spine
Loosely stuffed felt horns bend over. Stuff them hard, and for anything tall, like Smitty’s horn or the stalks on Boo’s disguise, slide a strip of craft foam or a tightly rolled tube of felt inside as a spine. I avoid wire in children’s costumes unless every end is capped and buried deep in the stuffing.
Glue for Position, Thread for Strength
I glue each horn base to the band, then wrap a few stitches of matching thread around band and horn together. The glue sets where it sits, and the thread takes the strain when someone hugs you or you pull a hood over the top.
Getting Blue and Green Makeup Off Without Stained Collars
Sulley, Mike, Randall and the Yeti all call for coloured face makeup, and strong blues and greens are the shades most likely to tint skin and rub onto hoods. I keep the colour to the forehead, temples and cheeks rather than the jawline, which keeps it off collars. Patch-test any face paint on the inside of your wrist a day ahead, set cream paints with a light dusting of translucent powder, and press it on rather than rubbing so it doesn’t streak.
To take it off, start with an oil-based cleanser or makeup remover, then wash with your usual face wash. Scrubbing with soap alone just spreads the pigment around. Bright colours can leave a faint tint for a few hours, which is normal and fades on its own.
Mike’s Eye Is Worth Getting Right
Across all 30, the pattern holds: get the colour base right, make one signature detail properly (Sulley’s spots, Mike’s eye, Celia’s snakes, George’s sock) and keep everything else simple. Sulley, Mike, Boo and Celia are the characters people name first, while Roz, Fungus, George and the CDA agents fill out a bigger cast, and the canister and door give you something different from a character. Pick breathable fabrics, soft props and shoes you can walk in. A carefully made eye on a plain green hoodie will beat an expensive costume with the details wrong every time.
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