Mikaeus, the Unhallowed, Krark-Clan Grunt, and The Reaper, King No More

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Krark-Clan Grunt on the battlefield
• The Reaper, King No More on the battlefield

Steps

1. Activate Krark-Clan Grunt 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 Krark-Clan Grunt ability Repeat

Results

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