Embalm

You point at one creature you can see within range, and their blood slowly begins to be transformed into a necrotic ichor. The target must succeed on a Constitution saving throw or take 1d8 necrotic damage and become poisoned. For the duration on your turn you can use your action to deal 1d8 necrotic damage to the target, each time you do so the damage increases by an additional 1d8. The spell ends if you use your action to do anything else. The spell also ends if the target is ever outside the spell’s range or if it has total cover from you. When the spell ends the creature is no longer poisoned.

When you cast this spell using a spell slot of 3rd level or higher, the initial damage increases by 1d8 for each slot level above 2nd.