Eruption

You create a volcanic eruption from a point on the ground that you can see within range. For the duration, intense pressure from trapped poisonous gasses causes a violent explosion out of the ground in a 100-foot-radius circle centered on that point, sending ash, gases, and volcanic rocks high into the air, and flows of fast moving magma on the ground.

For the duration of the spell, while a creature is in the spell's range, 

• At the end of each creature's turn, they must make a Constitution saving throw. On a failed save, they take 6d6 poison damage; and
• For creatures on the ground, at the end of a creature's second turn until the spell ends, creatures must make a Dexterity saving throw from being struck by flows of fast moving lava. On failed save, the creature takes 6d6 fire damage.