Mikaeus, the Unhallowed, Grim Poppet, and Krark-Clan Grunt

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Grim Poppet on the battlefield
• Krark-Clan Grunt on the battlefield

Steps

1. Activate Krark-Clan Grunt by sacrificing Grim Poppet
2. When Grim Poppet dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. This will be removed by its static ability, which will result in Grim Poppet having two -1/-1 counters instead
4. Resolve the Krark-Clan Grunt ability
5. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite -1/-1 counters
• Infinitely powerful Krark-Clan Grunt until end of turn