Thirst is a common Enchantment — Aura card from Mirage (MIR), collector number 99. Current market price: $0.05, TCGplayer market prices via Scryfall.
Enchant creature When this Aura enters, tap enchanted creature. Enchanted creature doesn't untap during its controller's untap step. At the beginning of your upkeep, sacrifice this Aura unless you pay {U}.