Blood Rain

This spell creates a cloud of foul energy that stays suspended in the air and makes a corrosive substance of a color similar to the one of blood. Every creature in a cylinder 40 feet tall and 15 feet in diameter must take a Dexterity saving throw when they enter the cylinder for the first time or start their turn there. Those that fail the saving throw take 3d6 acid damage, while those that succed take half damage.