Volcanic Spew

A line of flowing lava 60 feet long and 10 feet wide expels from you in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 5d10 fire damage and an additional 2d10 fire damage at the start of its next turn on a failed save, or half as much damage and no damage at the start of its next turn. 

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage (both initial and additional) increases by 1d10 for each slot level above 5th.