Xavier Sal, Infested Captain + Intruder Alarm + Serum Tank

Xavier Sal, Infested Captain

Intruder Alarm

Serum Tank

How it works

1. Activate Xavier Sal by tapping it and removing a counter from a permanent you control, creating a copy of an artifact creature token you control.
2. When the creature token enters the battlefield, Intruder Alarm and Serum Tank trigger.
3. Resolve the Intruder Alarm trigger, untapping all creatures.
4. Resolve the Serum Tank trigger, putting a counter on it.
5. Repeat.

This clever loop transforms Xavier Sal, Infested Captain into an endless token engine by leveraging Intruder Alarm's static ability to untap all creatures whenever a new one arrives. By paying the cost to populate, Xavier Sal creates a copy of an artifact creature token, which simultaneously triggers Serum Tank to stockpile charge counters and alerts Intruder Alarm to untap Xavier Sal so the process can begin anew. You can continuously tap and untap your captain to flood the board with infinite creature tokens and infinite ETB triggers, all while fueling Serum Tank to keep your hand fully stocked.