I bought a yard of pink tulle tonight at Walmart that I plan to use for the body for 98 cents and some thin pink ribbon for some of the tentacles for 49 cents, but envision using several different sizes and types of ribbons for the tentacles either in all pink, shades of pink or maybe pink and white.
I decided to do a little research on jelly fish and found this site and they are fascinating and bizarre.
The box jellyfish does have a heart nor a conventional brain, but have 4 parallel brains. They have 24 eyes (one pair on each of the four sides that is complex with 16 that are basically light-sensitive pits) and 60 bungholes. I have dated guys that are the embodiment of a jellyfish. Maybe I will end up naming one of my creations after them.
The pink tulle creation will be more of a box jellyfish but the Portugese Man-O-War looks like it would be an interesting challenge and have to give some thought on how I would interpret once into cloth.
This site has more information on jellyfish http://www.dnr.sc.gov/marine/pub/seascience/jellyfi.html
I had never even heard of a cannonball jellyfish before. They don't have tentacles but instead have a sort of a fused feeding apparatus and they don't grow very big - the site indicates 8-10 inches. There is a Mushroom Jellyfish that looks similar but doesn't have the brown band at the bottom and is flatter and larger - the site indicated they run 10-20 inches around.
The site also references a Moon jelly and says it is transparent and run 6-8 inches around, are the traditional saucer-shaped and you can tell what they are by the four pink horseshoe-shaped gonads that you can see through the bell. I didn't know that either, but that would explain why some jellyfish look pink in some photographs.
Here is another site that has actual pictures of videos jellyfish and even pictures of some of their stings, along with safety tips - don't think I will ever visit an ocean without wearing beach shoes and cautious about watching out more for dangers in the water after seeing them!
There is also a link on the same site to a free downloadable 70 page safety book.
Jellyfish coloring pages at:
This set of jellyfish is an embroidery design from the following (only to be used for personal use)