My daughter wanted an original and fun Jellyfish costume for Halloween.
We used an old bike helmet to keep the jellyfish on her head. The top was a pink plastic snow sled turned upside down. We drilled holes into the top and used zip-ties to connect the helmet to the sled. We covered the bike helmet with pink fabric so it would blend in. All of the jellyfish tendrils were made up of bath scrub puffs in various shades of pink and white. We cut the to length. We left them longer in the back and shorter in the front so she can see. They were hot glued on to the sled. We added a set of battery operated Christmas lights so she would glow at night. The top of the Jellyfish was a piece of fabric with newspaper under it to add height to the costume. She wore all pink and we attached some of the tendrils to her shirt since we cut them short so she can see.
This costume won a few prizes and she even made the local newspaper.