Acid rain

Acid pours from the sky in a 40 foot cylinder at a point you can see within range. Each creature that starts its turn in the cylinder or enters it for the first time an a turn must make a dexterity     

saving throw, on a failed save the creature takes 3d6 acid damage and is covered in acid for one minute. a creature covered in acid takes 3d6 acid damage t the start of each of its turns. Each time a creature fails the saving throw, they get covered in more acid taking an additional 1d6 acid damage at the start of its turn. A creature that succeeds takes half damage and is not covered in acid.