So I've been doing some messing around on the genetic wizard, and I feel like I may be on the right track, but I could be wrong.

Pair a male Spinner het clown, and breed it to a het clown, and the pattern is VERY similar to his snake. "Clown Spider" is the result. If you look at that pattern and slightly reduced it, and add the yellow, you have Ralph's snake.

The question is, where is the bright yellow coming from and whats causing the slightly reduced pattern? Pastel maybe for the color?

Just my 2 cents.