Many gels that foam will not go back to their original constituents. It's a one way street that usually ends up in a very hard substance.
But if you look at something like the mucus of the hagfish, you might have something. The hagfish will turn the surrounding water into a goo (reaction between sea water and mucus). I'd imagine you could foam that up much like you can do with the yolk of an egg (another possibility). It's easier to look at existing organic compounds than mess with man-made crap. But do you want a hagfish in your body?
Well on the topic of expandable body fillers lets take a rather mundain one. Fat. Looking at the arangemet of the atoms fat is HIGHLY compact when compaired to say starch or sugar from which it is formed. Now if there was a way to control such a back and forth conversion and a fat cell structure that could contain the expansion you'd have a fat cell that could expand to say 50 times it's orginal size and contract back.
But then you deal with the weight issue. That can be a problem for a 14ft wolfskunk. That's the whole idea behind a foam of some sort. Lots of empty space in large volumes.
Not really, the fat just expands not gain mass, thus a 15% body fat can expand to lets see. . .
Guessing 1000 pounds of Wolfskunk here equals 150 lbs of lard to work with.
Given 50 times volume expansion this results 7350 added pounds of volume at no extra weight or 201,831 cubic inches or 873.6 gallons or 3307 liters.
Anyway you look at it that is a lot of Wolfskunk coming from basicly nothing.
Dorian
PS: course post hoiliday binging plus forgetting to set the volume of the incomming fat could result is a Wolfskunk getting stuck in doorways by surprise.
