It foamed, and horrible things were happening to me.

And then another pair of legs we collaborated on were these look like jellyfish legs, also polyurethane.

They are most frequently made of latex, and can also be made out of synthetic materials including polyurethane.

So, we're talking about things like inflatable liners that can conform to the complex topological shape on the inside of a cave, foamed in place airlocks to deal with this complex topology, various ways of getting breathing gases made from the intrinsic materials of these bodies.