Erupting Fissure

The ground cracks and a wave of large stone spines erupt from you forming a line 100 feet long and 5 feet wide in a direction you choose. Each creature in the line must make a Dexterity saving throw. On a failed save, a creature takes 6d6 piercing damage, is knocked prone and has its speed reduced to 0 until the start of your next turn. On a successful save, the creature takes half damage, but suffers no other effect. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.