Yosei, the Morning Star, Gift of Immortality, and Altar of Dementia

Prerequisites

• Yosei, the Morning Star on the battlefield
• Gift of Immortality on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Yosei
2. When Yosei dies, it and Gift of Immortality trigger
3. Resolve the Yosei trigger, causing the next player in turn order to skip their next untap step
4. Resolve the Gift of Immortality trigger, returning Yosei from your graveyard to the battlefield
5. Resolve the Altar of Dementia ability
6. At the beginning of the end step, Gift of Immortality triggers, returning it from your graveyard to the battlefield attached to Yosei
7. Repeat during each turn unless you are the next player in turn order

Results

• Opponents skip their untap steps