So, here's the jellies i made. I bought some stuff called Crayola Modermagic Fusion, which is just a spongy clay that air dries. The blue one had little sparkles in it, for the blue slime. I mounted it on an old square base, shaped it the way i wanted it, gave it some little tentacles, and then dripped a copious amount of Aleen's Clear Gel Tacky Glue over the whole thing and let it dry. I also added some blue ink for darker streaks.
Total Time Expended: About 10 minutes. Super easy. It's pretty resilient too. The spongy body bends, and the glue gives it some protection. I threw it against the wall and it didn't break.
I tried something different with the ochre jellies: I melted orange wax in a pan, and then mixed with the Clear Tacky glue, then shaped them into globs and glued them to a base. I added some colored inks for a little distinction, and then covered with a fresh layer of tacky glue for that slimy shine.
Again, they only took a few minutes to create. The little squat one is actually hard as a rock, just a nugget of wax and glue. I think they turned out pretty well, and will suffice for actual monsters plunked on the game board.
I tried a third experiment as someone suggested, with silicone and foil. I wrapped tinfoil around my finger for a mold, and tried to fill it with clear silicone caulk that was tinted with orange die. I tried to put some Pam-no stick in there first, but it adhered to the foil pretty well anyway and just made a mess.
Mission failed on that one. I still would like to create a transparent ooze with the caulk though, i just don't know how to mold it correctly to allow it to dry. It would have had orange swirls through it.