Glacial Chasm, Wayward Swordtooth, and Ancient Greenwarden

Prerequisites

• Glacial Chasm on the battlefield
• Wayward Swordtooth on the battlefield
• Ancient Greenwarden on the battlefield

Steps

1. Play Glacial Chasm either from your hand or from your graveyard
2. When Glacial Chasm enters the battlefield, its second ability triggers, causing you to sacrifice another land you control
3. Play any land from your graveyard
4. At the beginning of your next upkeep, Glacial Chasm's cumulative upkeep ability triggers, allowing you to choose not to pay the cost and sacrifice it instead
5. Repeat

Results

• Prevent all damage that would be dealt to you