Caustic Spittle

You produce a small, viscous glob of acid and hold it in your belly. As an action, you can spit the acid at one creature within 20 feet. Make a ranged spell attack roll. On a hit, the target takes 3d6 acid damage plus 1d6 for each round since you cast the spell. Thus, the spell does 3d6 damage on the round you cast it, 4d6 on the round after, etc. If the spell ends before you make the attack, you must make a Constitution saving throw or take the damage yourself. The spell ends after the attack is made.