That depends on how old the spider is.
If it's under 18, it will be the spider's parents fault, resp. of the spiders' society.
If the spider is older than 18, it may be its own fault, especially if it was under druggs as a trafic part-taker.
In case the spider was TOO old, meaning its falling into your lap was caused by its sudden death due to heart attack or something, then there is no chance for you to accuse anyone else, except for the other driver. Just see to it that he is found guilty of having been drunk at the moment when the accident happened. I do hope you've got the money for that.