Earth Shatter

With a dramatic stamp of your foot or staff you send a violent tremor through the ground. Each creature in a 30-foot cone must make a Dexterity saving throw as the ground fractures from the impact and shock waves erupt upward. On a failed save, a creature takes 5d8 force damage and is knocked prone. On a successful save, a creature takes half as much damage and isn’t knocked prone. Until the end of your next turn, the ground within the 30-foot cone is treated as difficult terrain.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each spell slot above 3rd.