Black Death

You unleash the single most vile plague to ever exist. A black cloud of illness rolls out from you and fills a 150-foot Sphere centered on you. Each creature of your choice within that Sphere must make a Constitution saving throw. On a failed save, they take 11d10 Poison or Necrotic damage, your choice for each creature. A creature that fails the save also gains the Poisoned condition and 1d6 levels of Exhaustion. A creature with Immunity to the Poisoned condition does not have Immunity to the Poisoned condition from this spell. On a successful save, a creature takes the damage only. If you choose Poison, it ignores Resistance and treats Immunity as Resistance. This damage cannot reduce a creature to 0 hit points. While Poisoned, a creature has horrific, painful boils all over their body. When they take a Short or Long Rest or attempt to regain hit points, they must make a Constitution saving throw. On a failed save, they gain none of the benefits from the Long of Short Rest and don't regain hit points. Also while Poisoned, a creature has debilitating weakness, causing them to have the Incapacitated condition while Poisoned. This plague is highly contagious. If a Poisoned creature comes within 5 feet of a creature who hasn't been Poisoned by this spell, that creature must make a Constitution saving throw or become Poisoned and gain 1d6 levels of Exhaustion. The only way to remove the Poisoned condition from a creature, is to cast Greater Restoration spell or a spell of similar power.