Vyshaan's Coruption (boss)

you inflict the target with a disease of  blood corruption.
a diseased target takes 1d8 necrotic damage upon receiving the curse.

ad the start of each turn the target receive a additional 1d8 damage and the corruption spread to all creatures within 15 ft from the target.
when a creature dies while being diseased this way the body turns into a large pool of blood.

a greater restoration will remove the effect of the disease and makes the target immune for the disease for 1 minute.
when the lesser restoration is cast on the target the caster and target will each take 2d12 necrotic damage and then the effect ends on the target. 
creatures who are immune to diseases are immune to this spell