Sister Hospitaller, Phantom Train, and Mardu Siegebreaker

Prerequisites

• Sister Hospitaller in hand
• Phantom Train on the battlefield
• Mardu Siegebreaker in the graveyard
• available

Steps

1. Cast Sister Hospitaller by paying
2. When Sister Hospitaller enters, it triggers, returning Mardu Siegebreaker from your graveyard to the battlefield and causing you to gain life equal to its mana value
3. When Mardu Siegebreaker enters, it triggers, exiling Sister Hospitaller until Mardu Siegebreaker leaves the battlefield
4. Activate Phantom Train by sacrificing Mardu Siegebreaker
5. When Mardu Siegebreaker leaves the battlefield, Sister Hospitaller is returned from exile to the battlefield
6. Repeat from step 2
7. Resolve all Phantom Train abilities

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite lifegain triggers
• Infinite lifegain
• Infinite +1/+1 counters on a creature