Paroxysm is a uncommon Enchantment — Aura card from Exodus (EXO), collector number 94. Current market price: $0.20, TCGplayer market prices via Scryfall.
Enchant creature At the beginning of the upkeep of enchanted creature's controller, that player reveals the top card of their library. If that card is a land card, destroy that creature. Otherwise, it gets +3/+3 until end of turn.