This year our theme is Octonauts as chosen by our 3 year old. The Octonauts rescue and help sea animals so I chose to be the sea animal. My favorite sea animals are octopus and jellyfish. Since Professor Inkling of the Octonauts is an octopus and the 3 year old chose to be him, I went with the jellyfish.

There are a lot of similar costumes to be found on the internet. I am by far not the first one to do this. I am sure there are a good bit of videos and tutorials to be found as well. I decided not to look at these and just figure it out myself.

Supplies

I have put some links below to the same or similar items on Amazon. Need an umbrella and harness, velcro (rated to hold 5 pounds), spray adhesive, polyfill stuffing, LED strip with controller, battery pack, red and black wire, wire cutters/strippers, fairy lights, electrical tape, and fabric. I bought some solid, metallic fabric and some shear, see-through fabric. Use shear fabric for the jellyfish body and for all the tentacles that will have lights. You will need around 2.5-3 yards of the fabric you plan to use as the jellyfish body. I didn't buy enough and had to sew more on to make it big enough.

https://www.amazon.com/Krylon-K07010-11-Ounce-All-Purpose-Adhesive/dp/B000GLG7I2/ref=sr_1_3?crid=2CMC34T24YJSF&dchild=1&keywords=spray+adhesive&qid=1635709218&qsid=142-3942133-5858539&sprefix=spray+adhe%2Caps%2C109&sr=8-3&sres=B0752XM8VN%2CB000GLG7I2%2CB079D3XGKX%2CB000PCWRMC%2CB08NTXD3XB%2CB0065DL33O%2CB00114RCP0%2CB07739QBJ8%2CB008FP2RBM%2CB01DAEMBI6%2CB000A8AYO4%2CB0043BKMV4%2CB007POWZGG%2CB01LZQVQM8%2CB07RGWZ183%2CB001689P10%2CB001EUOAGK%2CB00B37Z61W%2CB00E7GCNKI%2CB09HFQ2TKP&srpt=BONDING_ADHESIVES

https://www.amazon.com/abcGoodefg-Battery-Holder-Plastic-Storage/dp/B078NK9GS2/ref=sr_1_1_sspa?crid=WYYREC6ZO0BM&dchild=1&keywords=8+aa+battery+holder+12v&qid=1635708444&s=hi&sprefix=8+AA%2Ctools%2C120&sr=1-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExQ09LQVNLSkJHOENXJmVuY3J5cHRlZElkPUEwNDIwOTAwVkxBQVVBTzdaN01OJmVuY3J5cHRlZEFkSWQ9QTA0NDcwMzkzN1lOUkIzMFJPVU9TJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

https://www.amazon.com/Changing-Lighting-Kitchen-Blacklight-Decoration/dp/B0816CHHWP?psc=1&pd_rd_w=Fhu2b&pf_rd_p=9b6c7c5b-711f-47e9-8510-2ca3ff59483f&pf_rd_r=07CM753GBKJ0DQE28Q8P&pd_rd_r=0a269c8d-293c-486e-82c4-890a9abb6f80&pd_rd_wg=XiQzR&ref_=sspa_dk_rhf_yoy_pt_sub_6&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzT1NFR0pYNk1FWjM0JmVuY3J5cHRlZElkPUEwODM1MzcwMzVUU0hHS1ozQ0pMRCZlbmNyeXB0ZWRBZElkPUEwNDE0MzY5MVM4SDBWSUo0NFJPVyZ3aWRnZXROYW1lPXNwX3JoZl95b3kmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

https://www.amazon.com/VELCRO-Brand-Sticky-Fasteners-Perfect/dp/B00006RSWT?ref_=ast_sto_dp&th=1

https://www.amazon.com/gp/product/B07YFR8XFK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B07S9GK1PL/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/Fairfield-Poly-Premium-Fiber-32-Ounce/dp/B004ALQ0M2/ref=sr_1_3?crid=1SRILURW81QQR&dchild=1&keywords=polyfill+stuffing&qid=1635708830&qsid=142-3942133-5858539&sprefix=poly%2Caps%2C109&sr=8-3&sres=B07CBQ8ZJ3%2CB004ALQ0M2%2CB002OUP6JE%2CB07DPZ92FD%2CB07KMKX8WJ%2CB000YZ7G44%2CB08LYJ66HN%2CB08M3BKRBW%2CB01N1UD94G%2CB08DH9Q2FP%2CB092V2CMLR%2CB003PA2AHI%2CB08QT8SF23%2CB08Y6CNHP7%2CB006I04VLU%2CB00TH2E3PA%2CB08XQN3HC5%2CB08YRGK279%2CB08BVVXS28%2CB0911RV4D3

https://www.amazon.com/BNTECHGO-Silicone-Flexible-Strands-Stranded/dp/B07HGTBC6T/ref=sr_1_3_sspa?crid=L1F992R0V2G7&dchild=1&keywords=red+wire+spool&qid=1635709152&sprefix=red+wire+spool%2Caps%2C112&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzTUlEU0g5ODZFSTNLJmVuY3J5cHRlZElkPUEwOTY3NDM2M1NUT1lLM0hVRkM5TyZlbmNyeXB0ZWRBZElkPUEwOTMzMTY0M0k2RzkwSVJIREszUCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Step 1: Jelly Body

This is step has a lot of information. This is the order I went in, but I was figuring it all out as I went. It may be easier to read all the info and choose the best order to go by.

Spread out your jelly body fabric. Open the umbrella and sit it upside-down in the center of the fabric.
Cut the fabric out around the umbrella. To try to get an even circle, I tied one end of a string to the pole and the other to a pen and used it like a compass to draw a circle around the umbrella. I wanted it a few inches bigger than the circumference of the umbrella so there would be enough slack to make the top of the jellyfish a bit bigger to allow for stuffing.
To attach the fabric to the umbrella I used velcro. Cut the velcro into small squares. I used one square in the center of every umbrella panel. I cut the squares in half and used one on each side of every panel. The best way to work with velcro for this is to line up and press together both sides of the velcro so you have one strip instead of 2. Then cut your squares. Peel the sticky back off the rough side and stick onto the umbrella in all the places mentioned (each panel has 3 pieces). Then peel the sticky back off the soft side which is now on the umbrella attached to the rough side.
Start at one panel. Pull the fabric up and press the fabric to the center velcro square. Work to the left, pull the fabric up and stick to the half square at the edge of the panel. This part is tricky, take the extra fabric extending past the corner and fold it over top the same velcro piece. The fabric is so shear that this extra fabric still sticks to the velcro. Some of this fold will also stick on to the edge velcro from the next panel. See photos to help understand this weirdness.
Repeat this all around the umbrella until all the fabric is attached.
Use a sharpie and number each section. Put the number on the fabric and the velcro it attached to. This is so if you have to take the fabric off, you can put it back on correctly. If you are following the same order I did, you will be removing the fabric to do the next part. For some extra hold and security, I put packing tape over each velcro section since the sticky of the velcro could still be felt through all the fabric.
Remove the fabric and sit aside.
Get out the LED strip. Plug the strip into the control thing that comes with it. Put 8 batteries in your battery pack and plug it into the control. Turn it on and make sure it all works.
Using velcro in the same manner as before, attach the LED strip in spirals from the bottom to the top of the umbrella top. Start with the control box. Place it so that the plug hangs off the end and spiral up. I was working with a strip I had already partially used so I didn't have enough to make it all the way. If you have excess, you can cut the strip following the instructions with the strip.
Now time to add the stuffing. We want the stuffing in thin layers so it diffuses the light. Take a chunk of stuffing and stretch it out thin. Spray the adhesive in a section the same size as the stuffing and then stick the stuffing on. Cover the entire umbrella top. Turn on the lights and see how it looks. You want to not be able to see the lights in lines as much as possible. If it still is clearly seen as individual lights in a line, add more layers of stuffing until the light seams even. I probably could have used more layers but you have to be careful to not put so much stuffing that you block out the light altogether.
Put the fabric topper back on.

Step 2: Tentacles

Cut your fabric into strips about 4 inches wide or so.
Fold in half lengthwise with right sides in and sew the long side. Leave the top open, sew down. Near the bottom sew in an arch to the end to make it rounded. Trim off the excess at the rounded end. Turn inside-out.
Decide on your pattern for the tentacles.
I had 20 tentacles so that made 2 on each panel. Attach the tentacles with velcro. One piece is sufficient per tentacle since the velcro is rated to hold 5 pounds. Put the velcro on one side of the tentacle and attach to umbrella so that the tentacle hangs open to the inside.
Take off one tentacle. Insert a fairy light. The best way I found to do this is to pinch the end of the light strip between your fingers and scrunch up the tentacle around your fingers as you inch your way to the end. Then hold the end of the fairy light from the outside and pull the fabric up around the lights.
Reattach the tentacle. Use velcro again to attach the battery pack to the umbrella.
Repeat with all the shear tentacles.

Step 3: Secure Battery Pack

This was a series of trial and error for me. At first I attached the battery pack to the pole of the umbrella at the top with velcro and ties. But the umbrella wouldn't close, which I needed it to do for transport. Then I used velcro to stick it to the inside on one of the panels about half way up. It holds, but it weighs the umbrella down so it leans in that direction hard. Finally I decided to stick it to the harness instead. To do this though, you have to make the cord longer to reach.

My battery box had already ben spliced so it was easy for me. If you buy the one in the link that comes with the DC plug, you will need to splice it.

Carefully cut through the protective cable about halfway down to expose the wire. Cut the wire. Slice down the sides of the protective cable to flay it open to have easier access to the wires on both ends. Now you have the battery box with exposed wires and the DC plug piece with exposed wires.
Use the wire cutters to strip a quarter inch of the covering off the red and black wires on both pieces to expose the copper insides.
Cut a length of wire from the red and black spools long enough to reach from the top of the umbrella to the harness. Strip both ends of each wire.
Take the black wire and twist the copper strands around the copper strands of the black wire on the battery box. Secure it by tightly wrapping it with electrical tape.
Do the same with the other end of the black wire to the wire on the DC plug piece.
Repeat this with the red wires.
Use electrical tape to tape the two wires to each other in intervals along its length so the wires stay together and are less likely to snag on stuff.

Put 2 strips of velcro on the harness. Stick the battery box on.

Plug the lights in. Use velcro on the umbrella to hold the connection point up so it doesn't dangle and get caught on stuff. Test to make sure everything is working.

Step 4: Strap In

Open the umbrella and turn on all the tentacle lights.

Put the umbrella in the harness. Plug in the battery pack. Turn it on.

Put the harness on.

Be awesome.

To take off:

Have a friend help you turn off all the lights if available.

Take off the harness.

Unplug the battery box.

Take umbrella out of harness.

Close umbrella.

****NOTE*****

The umbrella has 3 different height settings. For visibility purposes, the highest one is preferred. I found that as I walked, the stupid thing would fall down a setting or 2. It was near constant and SUPER annoying. To fix this, simply put a piece of velcro around the pole just under where it locks in for each setting. This will make it so you can't shorten the pole when you close the umbrella but it is SOOOOO worth it to not be fighting the thing the whole time.