Mikaeus, the Unhallowed, Phyrexian Altar, and Thunderblust

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Phyrexian Altar on the battlefield
• Thunderblust on the battlefield

Steps

1. Activate Phyrexian 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 Phyrexian 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 ETB
• Infinite LTB
• Infinite colored mana
• Infinite death triggers
• Infinite sacrifice triggers