Ebonflame

You select one creature you can see; the creature is engulfed in an aura of black flames. At the beginning of each of its turns, the creature must make a Constitution saving throw. If the saving throw fails, the creature takes 3d10 necrotic damage and is frightened; on its turn, it must move as far away from the caster as it can. The spell and the fright effect end only when the spell's duration expires.

Ebonflame can't be cast on a target that's underwater. The flames follow the affected creature when it moves, but if it is magically transported out of the flames, such as by teleportation, the spell ends.