Reality Acid is a common Enchantment — Aura card from Planar Chaos (PLC), collector number 45. Current market price: $0.26 (foil $4.82), TCGplayer market prices via Scryfall.
Enchant permanent Vanishing 3 (This Aura enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.) When this Aura leaves the battlefield, enchanted permanent's controller sacrifices it.