Xavier Sal, Infested Captain + Experiment Kraj + Devoted Druid + Tidewater Minion

Xavier Sal, Infested Captain

Experiment Kraj

Devoted Druid

Tidewater Minion

How it works

1. Activate Experiment Kraj using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
2. Activate Xavier Sal's first ability by tapping it and removing a -1/-1 counter from Experiment Kraj, creating a copy of any creature token you control.
3. Activate Experiment Kraj using Tidewater Minion's second ability by tapping it, untapping Xavier Sal.
4. Repeat.

This intricate laboratory relies on Experiment Kraj as the ultimate catalyst, granting itself the untap abilities of both Devoted Druid and Tidewater Minion while they sit nearby bearing +1/+1 counters. By tapping to untap Xavier Sal, Infested Captain and paying a -1/-1 counter to untap itself, Experiment Kraj generates an infinite loop of activations. Xavier Sal, Infested Captain then turns this mechanical engine into an army, harvesting those same -1/-1 counters to repeatedly populate any creature token you control.