Dioghaltas' Dreadful Downpour

Dark clouds spread and rain down blood in a 30-foot-radius, 10-mile-high cylinder for the duration, centered on a point you choose within range. When you cast this spell, and at the start of each of your turns until the spell ends, all undead within the spell's area of effect regain 1d4 hit points. Completely covering a creature from the rain blocks this effect.

If you cast this spell in an area where a ceiling blocks the clouds, such as inside a cave or building, the rain pours down from the ceiling instead and the hight of the cylinder equals the hight of the ceiling.

At higher Levels
When you cast this spell using a spell slot of 4th level or higher, the healing increases by 1d4 for each slot level above 3rd.