Athreos, Shroud-Veiled, Enduring Bondwarden, and Altar of Dementia

Prerequisites

• Athreos, Shroud-Veiled on the battlefield
• Enduring Bondwarden on the battlefield
• Altar of Dementia on the battlefield
• You control at least one other nontoken creature
• Enduring Bondwarden has at least one coin counter on it

Steps

1. Activate Altar of Dementia by sacrificing Enduring Bondwarden
2. When Enduring Bondwarden dies, it and Athreos' third ability trigger
3. Resolve the Enduring Bondwarden trigger, putting all counters from it onto another nontoken creature you control
4. Resolve the Athreos trigger, returning Enduring Bondwarden from your graveyard to the battlefield
5. When Enduring Bondwarden enters the battlefield, its backup ability triggers, putting a +1/+1 counter on the creature who had a coin counter placed on it, and giving it the printed ability until end of turn
6. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Enduring Bondwarden's power
7. Activate Altar of Dementia by sacrificing the nontoken creature with a coin counter on it
8. When the creature dies, it and Athreos' third ability trigger
9. Resolve the creature's trigger, putting all counters from it onto Enduring Bondwarden
10. Resolve the Athreos trigger, returning the creature from your graveyard to the battlefield
11. Resolve the Altar of Dementia ability from step 7, causing target player to mill cards equal to the sacrificed creature's power
12. Repeat

Results

• Infinite +1/+1 counters on target creature you control
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill