Become Reflection

After a successful attack roll has been made against you, use your reaction to cast this spell and to briefly adopt your attacker's visage.

Your attacker must make a WISDOM save against your Spell Save DC.  On a success, their attack happens as planned. On a fail, they realize they are not willing to attack themselves so maliciously, causing the attack to do half damage.  If their save fails by more than 5 points, they lose all confidence in their strike and the attack misses entirely.

The illusion ends immediately after the attack is resolved.