Trench Behemoth, and Fastbond

Prerequisites

• Trench Behemoth on the battlefield
• Fastbond on the battlefield

Steps

1. Activate Trench Behemoth by returning a land in the templated list from the battlefield to your hand, untapping Trench Behemoth
2. Play the land, triggering it and Fastbond
3. Resolve the land's ETB trigger, causing you to gain at least 1 life
4. Resolve the Fastbond trigger, dealing 1 damage to you
5. Repeat

Results

• Infinite landfall triggers
• Infinite lifegain triggers