Mikaeus, the Unhallowed, Shilgengar, Sire of Famine, and The Reaper, King No More

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Shilgengar, Sire of Famine on the battlefield
• The Reaper, King No More on the battlefield

Steps

1. Activate Shilgengar 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 Shilgengar ability Repeat

Results

• Infinite Blood tokens
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Infinite -1/-1 counters
• Infinite recursion of non-Human creatures you control