Tentacles?  How flexible do you want them?  What size? Medusa or giant octopus?

I've got a recipe for a very rubbery homemade material that might work quite well.  It isn't PM, but...  More later, I've got to get some sleep.

Sue

I used this as a mold material, so I guess we can include it here as a mold for papier mache.  But it would also be useful by itself for things like rubbery tendrils for a Medusa mask.  I'm a little vague as to how you would do it, but you may be able to cool the liquid until it becomes somewhat thick (but still liquid) and spoon it out, then let the liquid kind of string out over waxed paper.  Maybe it would air-cool quickly enough to be useful.  Or coat string with it.  Repeat coatings may make it thicker.

I tried this mold material and it is quite good, although it is sensitive to heat.  In fact, you can melt it down and re-use and reform it.  It feels like a very dense, foamy rubber, flexible, but quite sturdy. I tried to tear a simple mold and couldn't do it.  It appears infinitely reusable.

If you're going to start mixing this stuff, do it when you won't have any interruptions. Don't get sidetracked or you will regret it. (Trust me on this....)

And don't try to rush things and add all the ingredients at once, or add them in another order. I paid $16 for a gallon of glycerin through my vet & wasted quite a bit.

!!!DENATURED ALCOHOL IS A FUEL -- IT'S EXPLOSIVE!!! DO NOT ADD WHILE ON THE STOVE. DO NOT SMOKE WHILE USING. It is NOT rubbing alcohol. PAY ATTENTION!!!

RECIPE for large batch (smaller experimental batch at end of post)

4 1/2 pounds dry Gelatin (in flake, grainular or powder form) from a health food store.  This is the same stuff as plain Knox brand gelatin).  SMELL IT before you buy! If it smells like Jello, it's the right stuff.  Don't accept cornstarch -- some clerks don't know the difference.
9 cups of cool water (2.25 qts.)
13 cups Glycerin (3.25 qts or 9 lbs) (check with your veterinarian)
1 lb. glucose (I found it in bulk foods at Kroger/Fred Meyer stores, try health food stores, too)
1 oz. Denatured Alcohol (from hardware store)

Put the measured glycerin into a pot over LOW heat & start it heating. You do NOT add it to the gelatin unheated.

Pour the water into a large cooking pot & add the gelatin. Start mixing immediately & keep mixing until all the water & the gelatin is thoroughly mixed together (I used my hands). DON'T STOP mixing or it will separate & congeal in layers. When ready, the mess should be consistent in quality. If you do have to stop, cover the pot with a damp towel.

Place the pot of gelatin over LOW heat & start stirring when it begins to melt, and keep stirring until the gelatin is all melted and free from lumps. Then add the heated glycerin and stir until well blended. Then add the glucose and continue to mix until it is fully incorporated.

REMOVE FROM THE STOVE ENTIRELY. Now add the alcohol and stir until thoroughly blended with the rest of the mixture. It is now ready to use, & should be formed while warm.

NOTES:
Cooling the new mold can be accelerated by placing in the refrigerator.

I would tend to use dedicated utensils for this project.  Glycerin has fairly low toxicity (I still wouldn't eat it).  The denatured alcohol is the most toxic ingredient.  Everything else should be food grade.

The original recipe said to cook in a double boiler, but I didn't have one large enough, & didn't want to mess with 2 pots with rocks or marbles between, & just kept the temp on the lowest temp of my electric stove.

To make into another mold, just put back in the pot and heat at LOW temperature. DO NOT add water.

This material can be used many times. If it starts getting debris in it, just form a sieve made from wire window screening in a funnel shape and while the material is melted, pour it through into another container.

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1/3 SIZED RECIPE FOR TRIAL -- it still makes quite a bit

1.5 lbs gelatin
3 cups cool water
4 1/3 cups glycerin
1/3 lb glucose
1 Tablespoon denatured alcohol
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