Power Leak is a common Enchantment — Aura card from 30th Anniversary Edition (30A), collector number 71. Current market price: $0.53, TCGplayer market prices via Scryfall.
Enchant enchantment At the beginning of the upkeep of enchanted enchantment's controller, that player may pay any amount of mana. This Aura deals 2 damage to that player. Prevent X of that damage, where X is the amount of mana that player paid this way.