Spiders are co-dom, so you can get spider off spring from just one spider-gened parent. Axanthics are recessive, and you need the parents to BOTH carry the axanthic gene in order for the trait to show. ("het-axanthic" means the animals carries the gene, but looks normal)
So...to get a spider/axanthic snake:
1. Spider x axanthic ...then breed the baby spiders back to their axanthic parent.
2. Buy a spider that is already het-axanthic and mate it to another axanthic or het-axanthic. In this case you could get the combo in the first clutch...but you could also miss the odds. There's never any guarantees.
Is the Spider co Dom or Dom ?? Because thier is no super form proven yet but thier have been all spider have been all spider clutches or something of that sort...