Doomtide

You create a 15-foot radius sphere of black mist that appears as a mass of writhing tentacles centered on a point you choose within range. The fog spreads around corners. It lasts for the duration or until strong magical wind disperses the fog, ending the spell. Its area is heavily obscured.

When a creature enters the spell's area for the first time on a turn or starts its turn there, that creature must make a Wisdom saving throw. On a failed save the creature is stunned stunned for 1d6 rounds. You can choose yourself and one other creature of your choice to not be affected by this spell.

Also, the target can make a Wisdom saving throw at the end of each of its turns. On a success, the spell ends.

As a bonus action, you can move the fog up to 10 feet away from you on each of your turns. The vapors, being heavier than air, sink to the lowest level of the land, even pouring down openings.

Adapted from the 2e Prayers from the Faithful sourcebook.