Flesh Duplicate, and Felidar Guardian

Prerequisites

• Flesh Duplicate in hand
• Felidar Guardian on the battlefield

Steps

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

Results

• Infinite LTB
• Infinite ETB