Yes when I was a teenager the horror story was about a girl who had a pimple and it ended up being a spider egg that hatched. I think people love scary stories about spiders.
On the cactus front, I am sure we all have fears about things which seem to be a bit off kilter from the actual danger involved. I think it's natural - but I also think it is a healthy thing to slowly work through the fear, so it at least becomes a neutral feeling. The more fears you conquer in life, the more peaceful life becomes.
