Glacial Chasm + Ghirapur Orrery + Ramunap Excavator

Glacial Chasm

Ghirapur Orrery

Ramunap Excavator

How it works

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.

This elegant loop completely shields you from all incoming damage by leveraging Glacial Chasm's absolute protection while neatly sidestepping its heavy upkeep cost and attack restriction. Since Ramunap Excavator allows you to continually replay that same Chasm from your graveyard after sacrificing it to its own cumulative upkeep, you can safely reset its age counters turn after turn. Meanwhile, Ghirapur Orrery ensures you have the land drops to keep deploying your threats and lands smoothly, tying the entire defensive lock together.