We thought it was probably inspired by something by thought nothing of it. A friend recently saw it said "hey, that's a copy of a famous Conan painting, I used to have a postcard of it."
So today I Googled "Conan Snake Painting" and found it.
It's a copy of of the cover of "Conan The Usurper" painted by Frank Frazetta [link to painting from cover] and here is the copy we bought.
To be a true Cookie Monster vocal, said Mr. Conner, who signed some of the subgenre's biggest bands, including Sepultura and Fear Factory, "it's got to be really, really guttural. It should sound like they're gargling glass."
The article goes a bit far in generalising the Cookie Moster vocal sound. They lump all growling vocals as Cookieish, but most are missing the required childish shortening of words.
For a good example (IMHO) of the true Cookie sound, check out the recent Roadrunner United, "The All-Star Sessions" track 3 "Annihilation By The Hands Of God".