Requires

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