Re: What is Creepy Crawler 'plastigoop' made of.

The crawler you describe is a mixture of a block copolymer elastomer [synthetic 
rubber] and a plasticizing oil in the ratio of about 1:10.

The block polymer is manufactured and sold by Shell Chemical Co., Houston , 
Texas..Suitable oils include simple mineral oil from the drugstore.

To make these articles you'll also need a high intensity mixing device such as 
a Brabender or similar sigma bladed mixer. 

These rubber compounds will stretch several thousand percent and still snap 
back to its original shape when the strain is released.

My advice is to check with the folks at Shell regarding Kraton G elastomer 
compounds. They should be able to provide specific details.