Pattern of Rebirth + The Cauldron of Eternity + Boonweaver Giant + Altar of Dementia

Pattern of Rebirth

The Cauldron of Eternity

Boonweaver Giant

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Boonweaver Giant.
2. When Boonweaver Giant dies, The Cauldron of Eternity and Pattern of Rebirth trigger.
3. Resolve the Cauldron of Eternity trigger, putting Boonweaver Giant on the bottom of your library from your graveyard.
4. Resolve the Pattern of Rebirth trigger, putting Boonweaver Giant from your library onto the battlefield.
5. When Boonweaver Giant enters the battlefield, it triggers, returning Pattern of Rebirth from your graveyard to the battlefield attached to Boonweaver Giant.
6. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Boonweaver Giant's power.
7. Repeat.

This elegant loop relies on Boonweaver Giant as both the engine and the payload, seamlessly cycling between the battlefield and your library. When you sacrifice the Giant to Altar of Dementia, The Cauldron of Eternity safely tucks it away on the bottom of your library rather than letting it stay in the graveyard, while Pattern of Rebirth immediately snatches it back out. As the Giant re-enters, its own triggered ability reaches into your library or graveyard to reattach Pattern of Rebirth, priming the loop to repeat while the Altar mills your opponents out entirely.