Deceiving Counter (3.5e Martial Artist Maneuver)
From D&D Wiki
Your opponent penetrates your defense, but not without cost to himself
Level: Reactive 1
Prerequisite: Deceiving Stance
Description: If any assailant defeats your AC while in Deceiving Stance, you may make one attack at your full attack bonus for 1d4 points of damage. At level five, it goes up to 1d6, then up to 1d8 at ten. Then, at level twenty, another attack is added, and one more attack is added every five levels afterwards.