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Glowing Jellyfish Costume
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DIY Jellyfish Costumes

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DIY Jellyfish Costumes

DIY Glowing Jellyfish costumes

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Photo #1 - DIY Glowing Jellyfish costumes Photo #2 - Jellyfish costumes Photo #3 - DIY Jellyfish costume Photo #4 - Jellyfish Photo #5 - Jellyfish
Costume type:  Costumes for Women
Categories:Halloween Costumes, Animal Costumes

This homemade costume for women entered our 2012 Halloween Costume Contest.

A word from Helen, the 'Jellyfish' costume creator:

I was inspired by pictures of jellyfish costumes that I saw on other websites, plus the fact that they glow! I was going for something not too expensive and also not heavy or cumbersome so I decided to use a hybrid of methods I found on the web and added my own twist.


  • Inexpensive hat with a brim (choose one that fits you well)
  • Foam board (I reused from one of my kid's projects)
  • Bubble wrap- both big and small (recycled from home and bought some at the dollar store)
  • Drycleaning bags
  • 3 Thin wire battery operated warm led lights (purchased from Amazon)
  • 3 "tap on" battery operated lights- can purchase just about anywhere. The kind that are "stick on" and can attach with the adhesive back.
  • Iridescent and colored metallic tissue paper- from the dollar store
  • White duct tape and clear shipping tape
  • Iridescent mesh tubing- purchased at AC moore for 1/2 price. Can also find on the web easily.
  • Variety of white, clear and/or iridescent wired ribbon purchased on sale or with discount coupons. I used 1 and 1/2 rolls of both the wide and the more narrow widths.
  • Glue gun
  • Material - I used an old veil, but any sheer and/or iridescent material you like is fine.

How to make a jellyfish costume:

Started with the cowboy hat (sombrero seemed to flimsy as I wanted to be able to move about and dance easily).
Cut foam board in a 20 inch diameter circle (this was pretty large- I would do smaller next time, maybe 18 inches). Then cut a closefitting hole in the foamboard for the top of the hat to fit through (foam board is sitting on top of hat). I cut carefully each time to ensure the hole and hat fit my head closely.

I then applied hot glue around the top of the cowboy hat rim and firmly pressed the foamboard circle onto it. I poked a hole from underneath on each side of the hat in order to thread the battery operated light wire through from underneath the hat. Hot glued and adhered the 3 tap on lights underneath and behind where my head would fit – these make the large tentacles.

I covered the top of the hat with white duct tape and then glued metallic tissue all over the top and underneath of the hat. I also taped some of the colored tissue over each of the tap on lights. I used blue for one jellyfish and pink for the other one.

Hot glued the battery operated light control to the underside of the hat – one on each side (near where my ears were for balance). Made sure that tops were exposed so that I could change the batteries if needed.

To build up the top of the hat, I used a some white plastic bags, lots of drycleaning bags and even some toilet paper rolls – attached with the shipping tape. * make sure to keep the light string out!

Once I achieved the basic shape and height I wanted, I then taped the iridescent, metallic tissue all over the top with clear tape. Next, I attached the lights. No particular pattern, just enough to make sure the entire top would glow and be spaced out nicely. Used the clear packing tape to attach. Then I covered the entire top of the hat with the large bubble wrap bringing over the edge and attached it underneath (about an inch or so inside/underneath) with staples and glue.

Now it was time for the tentacles. For the three inside tentacles, I unraveled a long white loofah and cut them at my knees. Then attached them around the 3 tap on lights – so the light would shine down inside of the tentacle. I measured the mesh tubing, ribbon and small bubblewrap and cut so each tentacle came to my knees and varied the lengths a little. I scrunched the ribbon. Attached all to the underneath of hat with hot glue. I used an old veil found at the thrift store to cover the entire jellyfish, leaving about 3 inches extra underneath the hat, but you can use any sheer, iridescent material – just look for something you like!

Dressed all in white (can do all black too if you like). We glowed all night and had so many compliments and photos taken. The kids loved seeing us out trick or treating! Fun, fun, fun!

Rating: 4.1 of 5. Votes: 259

259 votes
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#1 comment by Ginger June 9, 2013

these are awesome!! I would love to see some pictures of the making process to go with the instructions!!

#2 comment by Debbie November 7, 2013

I made this costume for my 7-year-old and it got many "best costume ever!" votes with extra candy offerings. Thank you ladies for sharing and posting. I did have some troubles translating the instructions, but in the end it turns out great!

#3 comment by Jennifer September 3, 2014

I really want to make this but I'm having a hard time with some of the instructions. Any chance you took pictures of the process?

#4 comment by Nancy Breu September 13, 2014

We're going on a cruise for Halloween and I want to make these for my husband and I but am having trouble understanding how to do the light strings. The instructions call for 3 led thin wired lights but to put as hole on each side of the hat which sounds like you use only 2 of the light strings? Can you please elaborate? Thank you

#5 comment by Kelle September 30, 2014

Yes I have the same question about 3 led string lights but only two seem to be mentioned in the instructions. Not sure about where the third goes?
Taking a few girlfriends with me to visit one of my college daughters on Halloween and this costume is gonna be so much fun!!! Thanks!!!

#6 comment by Helen September 30, 2014

Hi all,
Sorry for the confusion. I'm sorry, but I did not take pictures as I was experimenting. I put one hole on each side of the foam/hat base circle. So, each light control was taped underneath the hat/jellyfish base with the light string strung through the hole. I think I had intended to use 3, but realized that two was enough light and the 3rd base made the hat too heavy for me. I hope that answers your questions, but if you have more, please ask away!

#7 comment by Kelle September 30, 2014

Thanks Helen!
Yes that makes sense. Thanks! One more question. Were those lights colored or white? It looks like the colored tissue illuminates the pink (or blue) and the lights are white, but thought to ask anyway. Sorry to pester!

#8 comment by Helen October 1, 2014

No bother at all! I did use colored lights. Pink for one and blue for the other costume. bought the lights (online). Very thin wire, led. I think they are called Fairy lights. check amazon for a selection. The tissue did not add as much color as I thought it would. Also, more of the white and irridescent materials looked better in the daylight.

#9 comment by Amy October 1, 2014

would you agree to loan it? I'd love to wear your brilliant creation and return it to you after Halloween. Save resources, etc.

#10 comment by Helen October 2, 2014

Sure. txt. me at 301-537-1546 and I can call you

#11 comment by Denise October 3, 2014

I too am trying to make this costume...Awesome by the way. Why the laundry bags? What purpose do they have? They are $3.00 a piece.

#12 comment by Helen October 3, 2014

$3?? I just used plastic dry cleaning bags that I took off my returned dry cleaned clothes. I used them around the top of the hat to fill in and shape- make more like the jellyfish shape. otherwise, it will look like just a hat with lights. Plastic grocery bags or even light trash bags would probably accomplish the same. I thought that bubble wrap was too expensive to use as filler, so I used it as the top layer only. Hope that makes sense!

#13 comment by Deb October 8, 2014

I am confused about the long white loofah. Not sure what or where you would purchase this. Could you explain further? Thanks. Love the idea. Me and another person I work with are going to dress up like this - great idea!!!



#14 comment by Helen October 9, 2014

The loofah is a scrubber usually sold in the bath department or at the dollar store. Easy and cheap. I think I bought mine at Walmart. It comes in a poof so you need to cut the string in the center that binds it together in order to unravel it. Hope that helps!

#15 comment by Deb October 11, 2014

Wondering how to keep the cowboy hat tighter to fit the head. Do you have ideas/suggestions. Thanks.


#16 comment by wendi October 12, 2014

What did you use the mesh tubing for?
Thanks, wendi

#17 comment by Helen October 12, 2014

Answering both #15 and #16 comments. I bought a hat the was pretty tight fitting- is yours a good fit? I guess duct taping the outside of the top might help? Maybe the hole you cut in foamboard is too big-- it should fit tightly around your head. I cut mine very small and then kept trying it on for fit. I just shaved more of the hole until I had a perfect fit, but snug.

The mesh tubing (iridescent) is part of the tentacles. If you look closely at the picture, you can see that the tentacles are made of twisted bubblewrap, ribbon and the mesh tubing. Hope that I helped!

#18 comment by Michelle October 13, 2014

Hi! Did you use 7ft led lights?

#19 comment by wendi October 14, 2014

Ok thank you, that did help! Doung this costume for my daughter who is 9! We are very excited to see how it turns out! Thank you

#20 comment by Helen October 14, 2014

hello all. The 7ft lights is a 7ft strand of lights. They are on a light wire (see Amazon to buy) and I wound them around the top of the hat and secured with clear packing tape.

Can't wait to see the pictures of your daughter's costume!

#21 comment by Deb October 14, 2014

It looks like you have a colored band of pink or blue for each costume on the bottom on your hat. Is that correct and if so what did you use? Thanks


#22 comment by Helen October 15, 2014

It does look like it! I covered the underside of the hat with the iridescent tissue (blue or pick) from the dollar store (or Michaels) and the "band" is where I carried it up over the edge of the hat. I used spray adhesive to glue the paper to the foamboard.

#23 comment by sue October 26, 2014

Why did you cover the top of the hat with white duck tape? Just wondering because I am using a white hat to start with. Thank you.

#24 comment by Helen October 27, 2014

Mine was a black cowboy hat- all they had available. You don't have to cover it since you have a white one.

#25 comment by Lauren December 2, 2014

At the top where the tentacles are, is that the veil? The thing that goes all the way around? Struggling to see what that is

#26 comment by Keisha December 6, 2014

Absolutely awesome!

#27 comment by Tami February 6, 2016

Hi...Would you consider selling it? I have no talent and would love to have it for The Special Olympics Polar Plunge in March.
God Bless...Tami

#28 comment by Brooke October 12, 2016

Hi, a bit late to the conversation, but why does your cowboy hat look so large? I'm trying to find one online that is flatter (to make it look bigger.) It looks like a Sombrero!

#29 comment by Helen October 12, 2016

Hi, added the hard posterboard (cut in circular shape) over the top of cowboy hat. Needed a firm base to bear the weight of the materials on top and the light's battery base under. So, yes, it really is the size of a sombrero! Cut out circle - I think it was 21 or 22 inches diameter and then cut out a circle/hole in the middle of that and fit the top of the cowboy hat through. I thought of using a sombrero, but it was too flimsy.

#30 comment by Brooke October 12, 2016

Ok so the size of the board is larger than the base of the hat and it is hanging off the sides? Or no? Could you add a larger board to the bottom of the hat as well to make your jellyfish look wider?

#31 comment by Helen October 12, 2016

not sure I understand your question, but if the hat rim is a 10inch diameter then yes, the cardboard (21 or 22 inch diam) is much larger. Basically like a sombrero, but much more firm. The top of the cowboy hat fits through the hole in the cardboard then I taped the hat rim firmly to the underside of the cardboard. make sure the hole in the cardboard is a close fit to your head. Hope that helps

#32 comment by Brooke October 12, 2016

Ok gotcha!I was thinking (thin) posterboard instead of cardboard when you said that. So I was wondering if it needed poster board on the bottom too...and make the ends meet...but since cardboard is thick, that makes sense now. So make it wider than the hat..around 18" and fold everything under! Thanks!

#33 comment by Jackson January 2, 2017

omg helen I love it!

#34 comment by Cory February 10, 2017

Your costumes came out great. We are about to embark on our jellyfish costume adventure tomorrow. It was helpful reading your responses to the questions people asked. We are hope ours come out half as good as yours!

#35 comment by Leah Medley September 8, 2017

How long would you say the construction takes, once you have all of the materials?

#36 comment by Helen September 11, 2017

Couple of days if you go about it carefully. I have now created several, so much faster. first time was more painstaking, but worked out just fine!

#37 comment by Vickie September 29, 2017

I love it. I am making 2 of the for Halloween this year. I just started buying the materials needed, just adding more tentacles due to wanting more flow. Hoping mine turns out good as I'm not very crafty.

#38 comment by Jen September 30, 2017

Im making one this weekend, or attempting to! Hoping they turn out as cute as yours!

#39 comment by Helen October 1, 2017

Vickie & Jen, I think they will turn out beautifully! Hope you will post pictures for us to see! Most important, make sure the hat & cardboard cutout (the head piece) fits well and is comfortable. Will make wearing it so much more pleasurable. Can't wait to see!

ps. Sorry folks, I just saw previous comments about the third light string? I think I only used 2 strings and then 3 press on battery operated lights (back of head). I hope that helps and sorry for any confusion

#40 comment by Debbie October 23, 2017

I'm currently making this for my 25 y/o daughter and friend. I found a farmers hat at Spirit of Halloween pop up store $9 each in black. I cut the foam board just as you described. I only have half a day today and tomorrow to complete this. Do you adhere the 3 puck lights to the underneath on the foam board on the back and sides? I fell in love with this costume the moment I saw it!

#41 comment by Kelle October 23, 2017

Hi Debbie!
It's been a few years since I made the three jellies that were a total hit all over campus during a Halloween/football weekend college visit. Literally epic! My daughter still talks about it! Anyway yes the large bulbs that touch/ click to light up go underneath The large poster board Hat/rim behind your head. The front rim underside should remain unobstructed because that's the only place you have for visibility. There will however be holes punched in on the sides and battery packs on each side glued to the underside Near your ear in order to power the fairy lights that are on the top mixed in with all of your iridescent paper and bubblewrap and someone you'll figure it out it kind of comes together magically. Good luck! This by far is the best costume ever! Hope that helps you!

#42 comment by Vickie October 30, 2017

I got mine all made. They look great

#43 comment by Kristin November 5, 2017

Thank you for this awesome idea. I rocked it and won first place at a big costume party. People took pictures and video and I got a ton of compliments.

#44 comment by Deb letscher October 1, 2018

I don't understand the cowboy hat if you use the head fitted umbrella top. Plus the foam board for the cowboy hat!

#45 comment by AJ October 27, 2018

The loofah idea is pure genius!

I have ribbon of every kind and thickness. Wired I crimped but I couldn't get a loose enough curl with any wide unwired ribbons. They all wound tightly and you couldn't tell if the costume was a jellyfish or Christmas gift at first. But the unwound loofah has the exact right "tentacle" texture! Thanks!

#46 comment by Helen October 27, 2018

You're welcome!! Hope you'll post pictures of your costume!!

#47 comment by Cynthia October 3, 2019

Are there any photos of the process??? It would be extremely helpful.

#48 comment by kimmy kervel August 18, 2020

thanks for sharing this is really helpful for me and also for my upcoming project so i hope you to add some more in future also

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