Unless you have a spider with a screen type body, you could wrap the spider in cheesecloth. I envision some fairly small pieces. Ricer holes are small.
How about grating the potatoes with a box grater using the larger holes then sprinkling the shreds into the oil. That might work better. With the grater, you would use raw potatoes. With the ricer they'd have to be cooked.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan