Fain's second ability by tapping it and removing a counter from a creature you control, creating a Treasure artifact token and a 1/1 Squirrel creature token that enters with at least two +1/+1 counters on it due to
Master Biomancer.
The Squirrel enters the battlefield, triggering
Intruder Alarm, untapping all creatures.
Repeat.
Once you have infinite Treasure and Squirrel tokens, you may activate