Duty Beyond Death is a uncommon Instant card from Tarkir: Dragonstorm (TDM), collector number 10. Current market price: $0.35 (foil $0.35), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, sacrifice a creature. Creatures you control gain indestructible until end of turn. Put a +1/+1 counter on each creature you control. (Damage and effects that say "destroy" don't destroy those creatures.)