Every material has advantages and disadvantages.
Wax had a lot of appeal as it took bright colorants and stretched and wrinkled
like real skin. One can work real fast and in fact has to as even a large piece becomes unworkable after 15 minutes or so. Fun, fun but got pretty old after the 35th year.
Darn things melt too.
The foamy stuff is Model Magic. It's a kids play material by Crayola™ but it stretches and takes bright colors. Really fun to work with
but the end product is pretty fragile so much as you'd like to you can't take them out in the dirt and play with them. They dissolve in water so the tub is out too.
Ceramic. This got overwhelming in a hurry. These last forever but to get bright colors takes three coats of underglaze. Since I don't like to go outside the lines this takes
Bronze. I did three. They'll dig them up as fossils someday.
Polymer Clay is our current medium. Still exploring but it has incredible colors, even flourescent and glow in the dark. Makes great insects and aliens. The teeth glow in the dark,
so do the eyes.