Perhaps he's referring to a Gak-like product? Something like a thick mixture of water and corn starch (I think those are the ingredients) that make up a non-Newtonian liquid, maybe, that oozes when left to relax, but stiffens up the moment force is applied?
I found a recipe for something different. Looks easy and relatively safe, but maybe not exactly permie.
I wish there were something simpler, but the effect is kinda fun. I almost want to experiment with it myself. Hmmm. I wonder if my young nieces and nephews might be interested? (heh heh. Slime everywhere...)
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein