Lavinia, Azorius Renegade, and Possibility Storm

Prerequisites

• Lavinia, Azorius Renegade on the battlefield
• Possibility Storm on the battlefield

Steps

1. Whenever an opponent casts a spell from their hand, Possibility Storm triggers, exiling the spell and allowing the player to reveal cards from the top of their library until they reveal a spell that shares a type with the exiled spell, and cast it without paying its mana cost
2. If the opponent chooses to cast the spell, Lavinia triggers, countering that spell since no mana was spent to cast it

Results

• Counter all spells opponents cast from their hands