I think what people are having issues with is the concept of something being allelic, and why you would never see something like “clown het cryptic” or “albino het candy”.
First of all, what is an allele?
It’s one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
So to break it down with pictures…
Ball pythons, like many animals are diploid. They have pairs of chromosomes, and as a result, pairs of genes.
A variant in one out of the two genes will lead to a visual morph in the case of a dominant/co-dominant/incomplete dominant trait, or it will be there but you can’t tell in the case of a recessive trait, like clown, cryptic, albino or candy.
The variant/mutation that cause clown/cryptic occurs at the same chromosomal location, but it is a different variant/mutaion.
When dealing with allelic morphs, you are limited to (2) per location. So this means a snake could be albino, candino, or candy, but never albino het candy. In terms of co-dominant allelic traits, it works much the same way. If Blackhead, Spider and HGW are all allelic, you could have a blackhead spider, or blackhead HGW, but never a blackhead spider HGW.