I think part of what completely freaked me out on this one was the fact that it was moving fast, with lots of side to side motion, and was almost jumping up off the ground at points (maybe a little exaggerated, but you get the idea)

Also, I grew up in an area with a lot of snakes, many of them poisonness. I can remember my Dad killing a copper head in the basement he was currently building, being warned about the water mocassins in the area ponds, and the rattlesnakes around there. Couple that to snakes being found in the bedroom, in the washing machine, dropping out of the rafters in the barn, hiding in the hay, cats trying to carry them into the house, and 4 older brothers who liked to torture me with them probably led to my fear of them. Now, if I happen to have any boys of my own, I just have to somehow find a way to keep them from knowing how scared I am of them. Insects, spiders, rats, mice are no problem, it's just those d*mn snakes (and lizzards to a small degree)

I have no problem with the caduceus though, I actually have a wall hanging I made with that on it after starting med school. Who knows why that doesn't bother me, but it doesn't.