Mikaeus, the Unhallowed, Luminous Broodmoth, and Catalyst Elemental

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Luminous Broodmoth on the battlefield
• Catalyst Elemental on the battlefield

Steps

1. Activate Catalyst Elemental by sacrificing it
2. When Catalyst Elemental dies, Mikaeus triggers, returning Catalyst Elemental from your graveyard to the battlefield with a +1/+1 counter on it
3. Activate Catalyst Elemental by sacrificing it
4. When Catalyst Elemental dies, Luminous Broodmoth triggers, returning Catalyst Elemental from your graveyard to the battlefield with a flying counter on it
5. Repeat

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite red mana