Mikaeus, the Unhallowed, The Reaper, King No More, and Bloodthrone Vampire

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• The Reaper, King No More on the battlefield
• Bloodthrone Vampire on the battlefield

Steps

1. Activate Bloodthrone Vampire by sacrificing The Reaper
2. When The Reaper dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. When The Reaper enters the battlefield, it triggers, putting a -1/-1 counter on it
4. Resolve the Bloodthrone Vampire ability Repeat

Results

• Infinite -1/-1 counters
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite recursion of non-Human creatures you control
• Infinitely large creature until end of turn