Festering Evil is a uncommon Enchantment card from Weatherlight (WTH), collector number 68. Current market price: $0.25, TCGplayer market prices via Scryfall.
At the beginning of your upkeep, this enchantment deals 1 damage to each creature and each player. {B}{B}, Sacrifice this enchantment: It deals 3 damage to each creature and each player.