Found this under my pillow, what do I do?
I had no idea spiders like you even needed pillows. But geez, if human hands that colossal are able to sneak their way under your pillow without you even noticing, it sounds like crap sleep is the least of your worries. Are you unearthing exclusively hands, or discovering other body parts too? Or have you been stockpiling humanoid extremities yourself and sleeping on them like a gigantic meaty stockpile, as if you're a spidery Smaug?
Hats off to you, then, honestly. Looks like you're living your best life. As long as you're dismembering giants with their happy consent, who am I to wag my finger at you? I suspect if I did, you'd cut that off too.