I debated on whether to even post this because I’m not totally satisfied with the outcome. However, I decided to go ahead because while there are a lot of images of Jellyfish Halloween Costumes on the internet, I had a difficult time finding instructions on constructing one.  So while I’m sure there are ways to tweak this, I hope these instructions can help guide you to make this costume and make it better!

Jellyfish Supplies

Jellyfish Halloween Costume


Please note that some of the yardage for the notions/fabrics will depend on the size of the jellyfish base. My base was approximately 15 inches round.

  • large plastic plate or platform for bottom of jellyfish – dollar store
  • large plastic bowl – dollar store
  • plastic bowl that is just slightly larger than your head with a flat bottom. It should be a snug fit. This will give support to the hat and is needed for stability as the top of the jellyfish hat is heavier.
  • baseball cap
  • glue gun & a full bag of glue sticks
  • 6 battery operated with remote LED lights – I originally used battery pack lights, but they are heavy. Remote lights also make it easier to turn on the lights without having to turn each individual light strand on by hand.
  • fiber fill
  • bubble wrap – dollar store
  • ribbon – at least two sizes and colors – amount of rolls will depend on how many tentacles you plan on placing, start with (1) 1″ sheer white ribbon and (2) 1 1/2″ colored ribbon
  • 1 yd. sheer shimmer fabric
  • 1 1/2 yd. fringe

How to Make a Jellyfish Halloween Costume:

I didn’t take photos of all the steps, so hopefully you can follow along using my drawings.

Have your supplies ready? I’m going to give you fair warning that this project takes a lot of glue. Also, don’t skimp with the glue on the base of the jellyfish. The base will have to support the LED battery packs, which hold 4 AA batteries a piece.

Full Jellyfish Instructions

Jellyfish Base

Steps 1 &2

Step 1. Take a large bowl and glue it down to the large platter or base. Let this dry completely before moving onto the next step. If you don’t want to use a bowl, you can just build up a mound using fiber fill.

Jellyfish Base Lights

Steps 3 & 4

Step 2. Evenly glue fiber fill onto the outside of the large bowl.

Step 3. Wrap one of the LED lights onto the fiber fill in a circular motion. Use small dots of hot glue to keep them in place. Leave enough wire out so that the battery pack can wrap under the brim of the base. Place more fiber fill over the LED lights to soften the glow.

Step 4. Wrap bubble wrap over the entire top and glue the wrap just under the brim. Keep the center of the base clear and free of any bubble wrap.

Jellyfish Base Head Attachment

Step 5 & 6

Step 5. Wrap shimmer fabric over the bubble wrap and glue just under the brim. Keep the center of the base clear of any fabric so the small bowl and hat can be glued on.

Step 6. Flip the hat over and glue the small bowl into the center of the base. Glue the baseball cap into the center of the bowl. Use lots of glue here. You may need to cut the brim of the cap so that it doesn’t stick out from the base. Also, you may want to sew straps onto the sides of the cap before gluing it in to help secure the cap under the chin. Now, glue the battery pack down – make sure the cover of the pack is facing out so you can change the batteries. Let this dry completely before moving on.

Jellyfish Tentacle Lights

Step 7 & 8

Step 7. Place the remaining 5 LED lights onto the underside of the base and use small dots of glue to keep them in place. Depending on the height of the child, you may need to wrap the lights around the underside of the base to shorten the length of the tentacles. Glue down the LED battery packs. Let this completely dry before moving forward.

Jellyfish Tentacles

Steps 9 & 10

Step 8. Glue fringe to the bottom outside edge of the small inner bowl. Next, glue fringe under the outside edge of the base (the large plate).  Let this dry.

Step 9. Cut ribbon to varying lengths and glue ribbon randomly to the underside of the base, keeping the ribbon strips inside of the fringe. When gluing on the ribbon strips, try to keep the opaque ribbons away from the face area, as these can block vision.

Step 10. To make some of the shorter tentacles, use some of the shimmer fabric and cut into triangle strips. Glue to the underside of the base.

Jellyfish Costume

Step 11. You’re all done! Have the wearer put on a black outfit, plop on the jellyfish hat, and you have a lighted Jellyfish Halloween Costume. Here’s my goofball trick-or-treater….

Jellyfish costume

If you have any questions, leave them in the comments below. What are your kids dressing up as for Halloween? Are you making their costume or buying it?

Lighted Jellyfish Costume

More Halloween Ideas…

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  1. Erlene, I think turned out really cute, and I love the added detail of the lights! I’m going to include your jellyfish costume in my Merry Monday Features next week 🙂

  2. cute idea! I especially like it because where we live it can be cold trick or treating and it would be easy to have the kids where a coat with this.