Unholy Aura

Evil energy washes out from you and coalesces in a grim aura in a 30-foot radius around you. Creatures of your choice in that radius when you cast this spell decrease light by one mark in a 5-foot radius and have advantage on all saving throws, and other creatures have disadvantage on attack rolls against them until the spell ends. In addition, when a celestial or an undead hits an affected creature with a melee attack, the aura oozes a horrid musk. The attacker must succeed on a Constitution saving throw or be poisoned until the spell ends.