Bartholomew’s Acrid Ray

You fire a ray of putrid acidic slime at an enemy you can see within range. Make a ranged spell attack against the target. On a hit the target takes 2d8 points of acid damage, and then an additional 1d8 points of acid damage at the end of it’s next turn unless they take an action to remove the acid. 

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the initial damage  increases by 1d8 for every slot level above 1st.