Kyouko used her Soul Gem to briefly end up in Sayaka's body, which was empty since Sayaka's Gem turned into a Grief Seed, whereupon she discovered Sayaka hadn't eaten in a while, so she bought food to feed her body with, after which... well, apparently the junk food didn't agree with Sayaka's system, necessating a trip to the bathroom and the subsequent handling by Kyouko of her naughty bits, and now she's giving Kyouko grief in the afterlife for that.
