Kentaro, the Smiling Cat, Cavern Harpy, Urza's Incubator, and Leyline of Transformation

Prerequisites

• Kentaro, the Smiling Cat on the battlefield
• Cavern Harpy in hand
• Urza's Incubator on the battlefield
• Leyline of Transformation on the battlefield

Steps

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

Results

• Infinite LTB
• Infinite ETB
• Infinite storm count