Felidar Guardian + Synth Infiltrator

Prerequisites

You have enough mana to cast Synth Infiltrator.

Steps

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