Pattern of Rebirth + Mortuary + Boonweaver Giant + Altar of Dementia

Pattern of Rebirth

Mortuary

Boonweaver Giant

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Boonweaver Giant.
2. When Boonweaver Giant dies, Mortuary and Pattern of Rebirth trigger.
3. Resolve the Mortuary 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 loop turns Boonweaver Giant into an endless, self-sustaining engine by exploiting how its own entering-the-battlefield ability interacts with the graveyard. When you sacrifice the Giant to Altar of Dementia, Mortuary catches it on its way to the graveyard and stacks it right back onto your library, perfectly positioned for Pattern of Rebirth to pluck it back out. As the Giant re-enters the battlefield, its search ability finds Pattern of Rebirth and snaps it right back onto the creature, ready to start the cycle anew. This elegant mechanical dance grinds any opponent down to dust by repeating the sacrifice indefinitely until their entire library is milled away.