Luminous Broodmoth, Nardole, Resourceful Cyborg, and Krark-Clan Grunt

Prerequisites

• Luminous Broodmoth on the battlefield
• Nardole, Resourceful Cyborg on the battlefield
• Krark-Clan Grunt on the battlefield

Steps

1. Activate Krark-Clan Grunt by sacrificing Nardole
2. When Nardole dies, its undying ability triggers if it didn't have a +1/+1 counter, and Luminous Broodmoth triggers if Nardole didn't have flying
3. Resolve the undying trigger, if applicable, returning Nardole from your graveyard to the battlefield with either a +1/+1 counter on it
4. Resolve the Luminous Broodmoth trigger, if applicable, returning Nardole from your graveyard to the battlefield with a flying counter on it if the creature is still in your graveyard
5. Resolve the Krark-Clan Grunt ability
6. Repeat

Results

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