Cookie Storm

You conjure a swirling storm of cookies in a 15-foot radius sphere centered on you. Each creature within that area must make a constitution saving throw or take 3d6 slashing damage, and are knocked prone. On your turn while the spell is active, every creature in the area takes 2d6 slashing damage. When your concentration is broken, a cookie explosion occurs and every creature in the area automatically takes piercing damage equal to your spell attack modifier.