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

Prerequisites

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

Steps

1. Activate Ashnod's Altar by sacrificing Thunderblust
2. When Thunderblust dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Activate Ashnod's Altar by sacrificing Thunderblust
4. When Thunderblust dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
5. Repeat

Results

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