Iona, Shield of Emeria, and Painter's Servant

Prerequisites

• Iona, Shield of Emeria on the battlefield
• Painter's Servant on the battlefield
• The same color chosen by Iona and Painter's Servant

Steps

1. Painter's Servant causes all spells to be the color named by it and Iona
2. Because all spells your opponent would cast will be the color named by Iona, your opponent cannot cast spells

Results

• Opponents cannot cast spells