Progenitor Mimic + Felidar Guardian

Progenitor Mimic

Felidar Guardian

How it works

1. Cast Progenitor Mimic by paying its mana cost, choosing to have it enter the battlefield as a copy of Felidar Guardian
2. When Progenitor Mimic enters the battlefield, it triggers, blinking Felidar Guardian.
3. When Felidar Guardian enters the battlefield, it triggers, blinking Progenitor Mimic. Choose to have Progenitor Mimic enter the battlefield as a copy of Felidar Guardian.
4. Repeat from step 2.