Metamorphosis Fanatic, Mardu Siegebreaker, and Yahenni, Undying Partisan

Prerequisites

• Metamorphosis Fanatic in hand
• Mardu Siegebreaker in the graveyard
• Yahenni, Undying Partisan on the battlefield
• available

Steps

1. Cast Metamorphosis Fanatic by paying
2. When Metamorphosis Fanatic enters, it triggers, returning Mardu Siegebreaker from your graveyard to the battlefield
3. When Mardu Siegebreaker enters, it triggers, exiling Metamorphosis Fanatic until Mardu Siegebreaker leaves the battlefield
4. Activate Yahenni by sacrificing Mardu Siegebreaker
5. When Mardu Siegebreaker leaves the battlefield, Metamorphosis Fanatic is returned from exile to the battlefield
6. Repeat from step 2
7. Resolve all Yahenni abilities

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers