Sidisi, Regent of the Mire, Thornbite Staff, and Altar of Dementia

Prerequisites

• Sidisi, Regent of the Mire on the battlefield
• Thornbite Staff on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Sidisi by tapping it and sacrificing the creature with mana value 0
2. When the creature dies, Sidisi triggers, untapping Sidisi
3. Resolve the Sidisi ability, returning the creature that creates creature token(s) on death from your graveyard to the battlefield
4. Activate Altar of Dementia by sacrificing the creature
5. When the creature dies, it and Sidisi trigger
6. Resolve the Sidisi trigger, untapping it
7. Resolve the creature's trigger, creating at least one creature token
8. Resolve the Altar of Dementia ability
9. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite mill
• Infinite self-mill