Thunderous Omen

You cause a small dark cloud to appear momentarily above one creature you can see within range. The target must succeed on a constitution saving throw or take 1d8 thunder damage. If the target has not willingly moved since the start of its last turn, it instead takes 1d12 acid damage.

The spell’s damage increases by one die when you reach 5th level (2d8 or 2d12), 11th level (3d8 or 3d12), and 17th level (4d8 or 4d12).