I put a spider on the back cover of the Fudebakudo book. People who know me well find this surprising, because I suffer from the relatively common affliction of arachnophobia — fear of spiders.
So maybe you don't like spiders either, but something deep down in my primal wiring really has a problem with them. I certainly can't voluntarily touch one of the beasties (well, tiny money spiders I can cope with… anything bigger than a thumbnail is out of bounds), but furthermore I can't comfortably handle photographs of them, or look at them. If a book has one on the cover (yes, even something like O'Reilly's Webmaster In A Nutshell, for example) in a room where I have to be, I'll discreetly turn it over so it's not in my peripheral vision (evolution has made sure that if you're frightened of something, just about the worst place for it to appear is in the corner of your eye).
I mention this because as an illustrator (albeit a cartoon illustrator) I can't really draw spiders — simply because I've avoided ever looking at them with the kind of intensity proper drawing requires. But (and this is about to get very nerdy) the cartoon spider on the back of Fudebakudo wasn't drawn, it was rendered in POV-ray. POV-Ray is a ray-tracer driven by a Scene Description Language. Huh? If you're not a nerd, then suffice to know I typed that spider. No, really: I didn't draw it, I typed it. If you don't believe me, here's the source code. Now that's scary.