Pia's Revolution deals no damage
Pia's Revolution "Whenever a nontoken artifact is put into your graveyard from the battlefield, return that card to your hand unless target opponent has Pia's Revolution deal 3 damage to them."
- Nontoken Artifact goes to the graveyard
- Pia's Revolution triggers
- Opp is given choice between paying 0 or giving me the card back
Problem: Opp's choice should be take 3 damage or give me the card back rather than paying 0 mana.