He is a very dark brown pastel yes. He does have interesting side markings for sure, I can see where you thought calico. I don't think it's YB, but with those weird sides..... Ask for a belly picture to know for sure.

If he's not asking a ridiculous amount, his sides might be worth toying around with. It might do something interesting to a gene like spider or enchi.

As a pastel, yeah he's really not very good. But man those sides just kill me. He'd be hard to pass up for the right price, just to see if he passed those sides on.

Gale