If someone were to breed two spiders together, there inherently *should* be a chance that under basic Mendellian genetics 1/4th of the babies from the pairing would be a spider that had two Dominant genes meaning when bred to anything it would produce the spider gene anywhere similar to how any other super form would work.

That being said, it seems that this is either impossible OR noone else has tried this and tested it enough to create an all-dominant Spider.

What are your thoughts and/or explanations on this?