Mikaeus, the Unhallowed, Morselhoarder, and Bloodthrone Vampire

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Morselhoarder on the battlefield
• Bloodthrone Vampire on the battlefield

Steps

1. Activate Bloodthrone Vampire 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 Bloodthrone Vampire ability Activate Morselhoarder by removing a -1/-1 counter from it, adding one mana of any color Repeat

Results

• Infinite colored mana
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinitely large creature until end of turn