Picture of Wearable Stay Puft Marshmallow Man Costume
This year I wanted to try something a little different then my usual mash-up costumes. I decided to go big or go home and what better way to make something big then to inflate it. So this year I am going to convert a 8’.5” foot tall 7’ wide Stay Puft Marshmallow Man Inflatable Lawn Decoration into a portable / wearable costume. More projects / photos at
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Step 1: Step 1: AC/DC?

Picture of Step 1: AC/DC?
The first step I would need to do is check to see if the fan motor will work on a portable DC power source. I was a little bit saddened when I read the sticker on the power supply. It read output voltage 12vac. If it was a synchronous motor the whole project would be canned but it turns out that when I hooked up a 12vdc power source the fan turned on and worked as it normally would. So I am guessing that either the label was printed incorrectly or the LED’s inside some how were part of an H-bridge to convert AC to DC.

Step 2: Step 2: Power

Picture of Step 2: Power
Next I had to find a 12v battery that would last long enough to keep this costume inflated at a party. This was done by using an old gel battery from a batter back-up. So I cut the wire that went to the wall adapter and soldered on some flat connectors that would allow me to connect to the battery. After testing the motor on this new battery the first thing I noticed was how heavy the battery was. So I decided to make a way to attach it to my belt. This one done by using a plastic coat hanger (the kind with the metal swivel hook at the top). I cut the hanger down to the length of the battery and used some duct tape to fasten it. I bent the metal part of the hanger to be more narrow and hung it from my belt. It was a little uncomfortable in the beginning but as I re-positioned it and bent it different ways it was not as bothersome anymore.
macgeek made it!10 months ago

AWWW ya beat me to the punch! :(
well.. great minds..

The differance between our two costumes, was I build the feet to have rubber souls, as well as slippers that I could walk in, I used a Dryer vent hose (plastic) from the air intake on the back of the heel, up to a power pack / Air pump I wear inside the costume (I used a flat Lithium / Ion type laptop external battery, gets me 12 hrs of run time) I used the same color mesh, with a back plastic sheet inside the costume so I can see outside, but you can't see me.

Great job, and DANG you for beating me!!! :)



My mother works for a radio station and let's just leave it to say that they had a giant 10' inflatable chicken costume that went with some of their programming. In many ways it wasn't much different than what you have here. The only real differences are that the feet were flat and some sort of stiff board on the bottom with two velcro straps that came up over my shoe. The battery and fan were attached to a heavy 5in or so nylon belt that was held by velcro and the fan had a tube of the same nylon material that went down to the costume to help fill it up. So you're right on track with what is professionally done. It's a hilarious costume and brought back some fun memories!

My day has started with a chortle; very funny Instructable-Thank you.

dpickett823 years ago
This is awesome. How easy do you think this costume would be to run long distances in (3-4miles)? Any changes you could make so it would be easier? If I'm 6'4", where would my face end up inside the costume? Thanks.
ddeb3 years ago
2 words: Porch Lights

I was gonna kill myself today, but you saved me! LOL

Some Dork3 years ago
Hahaha, awesome. Where in the world did you find a Stay Puft Marshmallow Man lawn decoration?
SubBass100 (author)  Some Dork3 years ago
Thanks! A lot of people laughed too when they saw it. I got it from
That is a great costume! Was it difficult or fun to wear, or both?
SubBass100 (author)  Penolopy Bulnick3 years ago
Thanks, It was quite fun to wear. Although I would make some changes to it to make it easier to wear in the future. One Idea would be to add a straw of sorts for a beverage or an access port to get things into and out of it! With that aside it was a blast to wear!
pjamestx3 years ago
That's fantastic! I just might have to give that a go next year :D
scoochmaroo3 years ago
Ah-mazing! So cool to see it on Subbass this morning, and here now! Really impressive work.