What the wizard did not tell you was that it takes two genes to get amelanistic and two different genes to get caramel.
Lets use cards for an illustration:
Amelanistic occurs when you have two red aces. The snake looks normal when there are two black aces or a black ace paired with a red ace.
Caramel occurs when you have two red jacks. The snake looks normal when there are two black jacks or a black jack paired with a red jack.
An amelanistic snake has two red aces and two black jacks. A caramel snake has two black aces and two red jacks. You take one ace and one jack from each snake to produce a baby. The result is a baby with a black ace paired with a red ace and a black jack paired with a red jack. The snake lookes normal and is heterozygous for amelanistic and heterozygous for caramel.
To be a butter, the baby has to be both amelanistic and caramel. It must have two red aces and two red jacks. Because each parent provides one ace and one jack for each baby, both parents must have at least one red ace and at least one red jack to pick from. Otherwise no butters are produced.
Hope this helps.
Paul Hollander