Marina Vendrell, Unholy Annex // Ritual Chamber, Intruder Alarm, and Aphetto Alchemist

Prerequisites

• Marina Vendrell on the battlefield
• Unholy Annex // Ritual Chamber on the battlefield
• Intruder Alarm on the battlefield
• Aphetto Alchemist on the battlefield
• Ritual Chamber is locked
• Marina and Aphetto Alchemist do not have summoning sickness

Steps

1. Activate Marina by tapping it, unlocking Ritual Chamber
2. Ritual Chamber triggers, creating a 6/6 Demon creature token with flying
3. When the Demon enters the battlefield, Intruder Alarm triggers, untapping all creatures
4. Activate Marina by tapping it, locking Ritual Chamber
5. Activate Aphetto Alchemist by tapping it, untapping Marina
6. Repeat

Results

• Infinite ETB
• Infinite creature tokens
• Infinite untap of all creatures
• Infinite mana creatures you control can produce