Athreos, Shroud-Veiled, Enduring Bondwarden, and Ashnod's Altar

Prerequisites

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

Steps

1. Activate Ashnod's Altar by sacrificing Enduring Bondwarden, adding
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. Activate Ashnod's Altar by sacrificing the nontoken creature with a coin counter on it, adding
7. When the creature dies, it and Athreos' third ability trigger
8. Resolve the creature's trigger, putting all counters from it onto Enduring Bondwarden
9. Resolve the Athreos trigger, returning the creature from your graveyard to the battlefield
10. Repeat

Results

• Infinite +1/+1 counters on target creature you control
• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers