Boonweaver Giant + Altar of Dementia + Shade's Form

Boonweaver Giant

Altar of Dementia

Shade's Form

How it works

1. Activate Altar of Dementia by sacrificing Boonweaver Giant
2. When Boonweaver Giant dies, Shade's Form triggers, returning Boonweaver Giant from your graveyard to the battlefield
3. When Boonweaver Giant enters, it triggers, returning Shade's Form from your graveyard to the battlefield attached to Boonweaver Giant.
4. Resolve the Altar of Dementia ability from step 1.
5. Repeat.