Felidar Guardian + Mercurial Pretender

WU identity

Commander legal

The 2 combo pieces

• Felidar Guardian
• Mercurial Pretender

How to execute it

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

What the combo produces

• Infinite creature LTB
• Infinite ETB