Koll, the Forgemaster, Deathrender, and Ashnod's Altar

Prerequisites

• Koll, the Forgemaster on the battlefield
• Deathrender on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing the creature with Deathrender attached, adding
2. When the creature dies, Koll and Deathrender trigger
3. Resolve the Koll trigger, returning the creature from your graveyard to your hand
4. Resolve the Deathrender trigger, putting the creature from your hand onto the battlefield and attaching Deathrender to it
5. Repeat

Results

• Infinite colorless mana
• Infinite death triggers
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers