Cauldron of Souls, Corridor Monitor, Ridgescale Tusker, and Ashnod's Altar

Prerequisites

• Cauldron of Souls on the battlefield
• Corridor Monitor on the battlefield
• Ridgescale Tusker on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Cauldron of Souls by tapping it, giving Ridgescale Tusker and Corridor Monitor persist until end of turn
2. Activate Ashnod's Altar by sacrificing Corridor Monitor, adding
3. Corridor Monitor dies, triggering its persist ability, returning itself from your graveyard to the battlefield with a -1/-1 counter on it
4. Corridor Monitor enters the battlefield, untapping Cauldron of Souls
5. Activate Ashnod's Altar by sacrificing Ridgescale Tusker, adding
6. Ridgescale Tusker dies, triggering its persist ability, returning itself from your graveyard to the battlefield with a -1/-1 counter on it
7. Ridgescale Tusker enters the battlefield, putting a +1/+1 counter on each creature you control
8. Repeat

Results

• Infinite +1/+1 counters on all other creatures you control
• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers