Death Armor

D&D 2024 spell: Death Armor. Source: Forgotten Realms: Heroes of Faerûn. level 2, school Necromancy, casting time 1 action, range Touch, duration 1 hour

For the duration, an inky aura surrounds one creature you touch. The target has Advantage on Death Saving Throw, and once per turn, when a creature within 5 feet of the target hits it with a melee attack roll, the attacker takes 2d4 Necrotic damage.

Source: Forgotten Realms: Heroes of Faerûn, p. 143 - Licenses and attribution