Channel Harm is a uncommon Instant card from Fate Reforged (FRF), collector number 7. Current market price: $0.20 (foil $0.43), TCGplayer market prices via Scryfall.
Prevent all damage that would be dealt to you and permanents you control this turn by sources you don't control. If damage is prevented this way, you may have Channel Harm deal that much damage to target creature.