Counter Shock

You point your finger, and the creature that damaged you is momentarily overloaded with electrical energy. The creature must make a Constitution saving throw. On a failure, the target takes 2d10 lightning damage and cannot take reactions until the end of their next turn. On a success, they only take half damage

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d10 for each slot level above 1st.