Fraying Sanity is a rare Enchantment — Aura Curse card from Fallout (PIP), collector number 175. Current market price: $0.55 (foil $0.73), TCGplayer market prices via Scryfall.
Enchant player At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.