Lavinia, Azorius Renegade, and Knowledge Pool

Prerequisites

• Lavinia, Azorius Renegade on the battlefield
• Knowledge Pool on the battlefield

Steps

1. Whenever a player casts a spell from their hand, Knowledge Pool triggers, exiling that spell and allowing them to cast a spell exiled by it without paying its mana cost
2. When an opponent casts a spell this way, Lavinia triggers, countering that spell

Results

• Counter all spells opponents cast that are created by Knowledge Pool
• Exile all spells players cast from their hands