I've been mostly reading this thread and trying to come up with my own opinions.
I can see both sides of this argument. At first glance, it does look like a normal. The color is is way off for a spider. I've seen some dark spiders, but not that dark. However, the head stamp does faintly resemble a spider and I do some some spider webbing (although not much at all).
I don't know if I would jump out and say that was 100% a spider, but I definitely can see the potential (just like you aren't sure if it's a yellowbelly so you sell it as a possible yellowbelly). Same rules apply here. I would call this snake a possible spider.
Like others have said, the only true way to determine if it is without a doubt a spider is to breed it to a normal. However, even with this option you run the risk of producing low quality spiders if this is truly a spider. Would I breed it? Personally: No. I would much rather spend my money on a spider that is a killer example of the morph rather than waste my time/money on something that might be a spider. Spider is one of those morphs that is usually very, very obvious and you can tell an animal has spider in it from a mile away. With this snake, it's questionable. But like everyone else said, pictures of mom and dad may help to determine if it's not only a spider, but if there is something else going on that might distort the patter.
Good luck with your snake!
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