Xavier Sal, Infested Captain + Intruder Alarm + Yorvo, Lord of Garenbrig

Xavier Sal, Infested Captain

Intruder Alarm

Yorvo, Lord of Garenbrig

How it works

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

This fascinating loop hinges on Xavier Sal, Infested Captain using its tap ability to populate your existing creature tokens, which immediately turns Intruder Alarm into an untap engine by waking your entire board whenever a new token arrives. Meanwhile, Yorvo, Lord of Garenbrig happily watches these creatures enter to grow larger with fresh +1/+1 counters, providing a convenient pool of counters for Xavier Sal to strip away in order to restart the process. Because Intruder Alarm untaps Xavier Sal right back up alongside your other creatures, you can repeat this tap-and-populate cycle as many times as you like to flood the board with tokens and infinite triggers.