Corrosive Smite

You magically coat your weapons with a powerful acid. The first time you hit with a weapon attack during this spell's duration, you deal an extra 1d6 acid damage. At the start of each of the targeted creature's turns after they are hit with this attack, they're AC is reduced by 1, then the creature must succeed on a constitution saving throw or take 1d6 acid damage.

At higher levels, increase the initial acid damage and the damage done each turn by 1d6 per level cast above 1st.