Reality Acid is a common Enchantment — Aura card from Time Spiral Remastered (TSR), collector number 81. Current market price: $0.29 (foil $1.32), 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.