Hoverguard Sweepers, Morophon, the Boundless, and Leyline of Mutation

Prerequisites

• Hoverguard Sweepers in hand
• Morophon, the Boundless on the battlefield
• Leyline of Mutation on the battlefield

Steps

1. Cast Hoverguard Sweepers by paying
2. When Hoverguard Sweepers enters, it triggers, returning itself from the battlefield to your hand
3. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite storm count
• Return any number of creatures to their owners' hands