Xavier Sal, Infested Captain, Intruder Alarm, and Tribute to the World Tree

Prerequisites

• Xavier Sal, Infested Captain on the battlefield
• Intruder Alarm on the battlefield
• Tribute to the World Tree on the battlefield
• There is at least one counter on a permanent you control
• You control a creature token with base power 2 or less

Steps

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

Results

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