How To Get a Spiker Out of the Bathtub:
If you don't have any bug spray - use hairspray! If you spray spiders with hair spray, it'll "freeze" their legs so they can't move/crawl up and out of the tub. Then you can safely remove the spider without fear that it's going to jump out at you or crawl up your arm. I never knew about this awesome trick.
Hope it'll help you in future battles =)