Primal Prayers, Guide of Souls, and Cavern Harpy

Prerequisites

• Primal Prayers on the battlefield
• Guide of Souls on the battlefield
• Cavern Harpy in hand

Steps

1. Cast Cavern Harpy by paying due to Primal Prayers, if able, or by paying its mana cost
2. When Cavern Harpy enters the battlefield, it and Guide of Souls trigger
3. Resolve the Guide of Souls trigger, causing you to get and gain 1 life
4. Resolve the Cavern Harpy trigger, returning it from the battlefield to your hand
5. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite lifegain triggers
• Infinite lifegain
• Infinite storm count