Xavier Sal, Infested Captain, Intruder Alarm, and Sharp-Eyed Rookie

Prerequisites

• Xavier Sal, Infested Captain on the battlefield
• Intruder Alarm on the battlefield
• Sharp-Eyed Rookie on the battlefield
• You control a creature token that has base power or toughness that is greater than Sharp-Eyed Rookie's power or toughness
• You control a permanent that has a counter on it

Steps

1. Activate Xavier Sal's first ability by tapping it and removing a counter from a permanent you control, creating a copy of another creature token with base power or toughness that is greater than Sharp-Eyed Rookie's power or toughness
2. When the Wolf token enters the battlefield, Intruder Alarm and Sharp-Eyed Rookie trigger
3. Resolve the Intruder Alarm trigger, untapping all creatures
4. Resolve the Sharp-Eyed Rookie trigger, putting a +1/+1 counter on it and creating a Clue artifact token
5. Repeat

Results

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