Triskaidekaphobia is a rare Enchantment card from Shadows over Innistrad (SOI), collector number 141. Current market price: $0.24 (foil $0.46), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, choose one — • Each player with exactly 13 life loses the game, then each player gains 1 life. • Each player with exactly 13 life loses the game, then each player loses 1 life.