Mikaeus, the Unhallowed, Ashnod's Altar, and Moonshadow

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Ashnod's Altar on the battlefield
• Moonshadow on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Moonshadow
2. When Moonshadow dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect
3. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite colorless mana
• Infinite death triggers
• Infinite sacrifice triggers