Cauldron of Souls, Corridor Monitor, Goblin Bombardment, and Verdurous Gearhulk

Prerequisites

• Cauldron of Souls on the battlefield
• Corridor Monitor on the battlefield
• Goblin Bombardment on the battlefield
• Verdurous Gearhulk on the battlefield
• Corridor Monitor and Verduous Gearhulk do not have a -1/-1 counter on them

Steps

1. Activate Cauldron of Souls by tapping it, giving Verdurous Gearhulk and Corridor Monitor persist until end of turn
2. Activate Goblin Bombardment by sacrificing Corridor Monitor
3. When Corridor Monitor dies, its persist ability triggers, returning itself from your graveyard to the battlefield with a -1/-1 counter on it
4. When Corridor Monitor enters the battlefield, it triggers, untapping Cauldron of Souls
5. Activate Goblin Bombardment by sacrificing Verdurous Gearhulk
6. When Verdurous Gearhulk dies, its persist ability triggers, returning itself from your graveyard to the battlefield with a -1/-1 counter on it
7. When Verdurous Gearhulk enters the battlefield, it triggers, putting a +1/+1 counter on itself and Corridor Monitor, and two +1/+1 counters on any other creature(s) you control
8. Resolve both Goblin Bombardment abilities, dealing 2 damage to any target
9. Repeat

Results

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