Mikaeus, the Unhallowed, Blasting Station, and Safehold Elite

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Blasting Station on the battlefield
• Safehold Elite on the battlefield

Steps

1. Activate Blasting Station by tapping it and sacrificing Safehold Elite
2. When Safehold Elite dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When Safehold Elite enters, Blasting Station triggers, untapping Blasting Station
4. Resolve the Blasting Station ability from step 1
5. Activate Blasting Station by tapping it and sacrificing Safehold Elite
6. When Safehold Elite dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
7. When Safehold Elite enters, Blasting Station triggers, untapping Blasting Station
8. Resolve the Blasting Station ability from step 5
9. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite damage
• Infinite sacrifice triggers
• Infinite mana creatures you control can produce
• Infinite untap of creatures you control