Mikaeus, the Unhallowed, Morselhoarder, and Hammerhead, Maggia Boss

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Morselhoarder on the battlefield
• Hammerhead, Maggia Boss on the battlefield

Steps

1. Activate Hammerhead by sacrificing Morselhoarder
2. When Morselhoarder dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect
3. Resolve the Hammerhead ability Activate Morselhoarder by removing a -1/-1 counter from it, adding one mana of any color Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite colored mana
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers