Glacial Chasm, The Gitrog Monster, and Ramunap Excavator

Prerequisites

• Glacial Chasm on the battlefield
• The Gitrog Monster on the battlefield
• Ramunap Excavator 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 and The Gitrog Monster's first ability trigger
5. Resolve The Gitrog Monster trigger, sacrificing Glacial Chasm
6. Resolve the Glacial Chasm trigger, choosing not to pay and doing nothing as Glacial Chasm is no longer on the battlefield
7. Repeat

Results

• Prevent all damage that would be dealt to you