Comet of Casandora

You call forth a comet from the astral sea. Sending it to crash into the earth with devastating explosive force.

Any creature within a 50ft radius of a target area must make a Dexterity saving throw. On a failed save, the targets take 10d10 force damage and 5d10 fire. Any creature that is killed by this spell is squashed flat. Any creature not killed by this spell is knocked prone and stunned. Any objects in the 30ft radius take full damage and will explode if destroyed this way. All terrain within the radius of the spell becomes rough terrain.

On a successful save, the targets take half damage and are knocked prone.

The caster must be outside to use this spell.