Prismari, the Inspiration, and Insidious Will

Prerequisites

• Prismari, the Inspiration on the battlefield
• Insidious Will in hand
• available

Steps

1. Cast any other instant or sorcery by paying its mana cost
2. Holding priority, cast Insidious Will by paying its mana cost, targeting the instant or sorcery cast in step 1
3. Insidious Will's storm ability triggers, creating at least one copy of Insidious Will targeting the original Insidious Will
4. Resolve a copy of Insidious Will, copying Insidious Will targeting the original Insidious Will
5. Repeat step 4

Results

• Infinite magecraft triggers