Xavier Sal, Infested Captain, Intruder Alarm, and Serra Redeemer

Prerequisites

• Xavier Sal, Infested Captain on the battlefield
• Intruder Alarm on the battlefield
• Serra Redeemer on the battlefield
• You control at least one creature token with base power 2 or less
• Xavier Sal does not have summoning sickness
• There is a removable counter on a permanent you control

Steps

1. Activate Xavier Sal by tapping it and removing a counter from a permanent you control, creating a copy of a creature token you control with base power 2 or less
2. When the creature token enters the battlefield, Intruder Alarm and Serra Redeemer trigger
3. Resolve the Intruder Alarm trigger, untapping all creatures
4. Resolve the Serra Redeemer trigger, putting two +1/+1 counters on the creature token
5. Repeat

Results

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