Mikaeus, the Unhallowed, Bloodied Ghost, and Bloodthrone Vampire

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Bloodied Ghost on the battlefield
• Bloodthrone Vampire on the battlefield

Steps

1. Activate Bloodthrone Vampire by sacrifiicing Bloodied Ghost
2. When Bloodied Ghost dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. When it enters, Bloodied Ghost will put a -1/-1 counter on itself, removing the +1/+1 counter
4. Resolve the Bloodthrone Vampire ability
5. Repeat
6. Activate Bloodthrone Vampire by sacrificing Bloodied Ghost
7. When Bloodied Ghost 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
8. Resolve the Bloodthrone Vampire ability Repeat

Results

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