Creepy Crawlers allowed young children to create their own rubbery creature goodies. The creatures made were initially bugs, snakes, and other things that young boys liked to scare people with.
The main set featured an oven (this toy is probably the boy's equivalent of an Easy-Bake Oven) and some metal molds. It also came with a few bottles of different colored liquid rubber/plastic material. One would squirt the liquid stuff into the molds anyway you wanted and then proceed to place the mold into the oven. A short time later, the molds would be retrieved and a neat little rubbery creature was made!
Later sets featured bigger and more creative creatures such as multi-parted monsters with interchangeable body parts. I believe it was also third-party licensed although I cannot recall any of the themes/characters.