Yannik, Scavenging Sentinel, Lumbering Battlement, and Felidar Guardian

Prerequisites

• Yannik, Scavenging Sentinel in hand or in the command zone
• Lumbering Battlement in hand
• Felidar Guardian on the battlefield
• plus enough mana to pay for commander tax, if applicable available

Steps

1. Cast Yannik either from your hand or from the command zone by paying plus commander tax, if applicable
2. Yannik enters the battlefield, exiling Felidar Guardian and putting a +1/+1 counter on any other creature you control
3. Cast Lumbering Battlement by paying
4. Lumbering Battlement enters the battlefield, exiling Yannik
5. Yannik leaves the battlefield, returning Felidar Guardian from exile to the battlefield
6. Felidar Guardian enters the battlefield, blinking Lumbering Battlement
7. Lumbering Battlement leaves and enters the battlefield, returning Yannik from exile to the battlefield, and triggering Lumbering Battlement's enters-the-battlefield ability
8. Yannik enters the battlefield, exiling Felidar Guardian and putting a +1/+1 counter on any other creature you control
9. Resolve the Lumbering Battlement trigger, exiling Yannik
10. Repeat from step 5

Results

• Infinite +1/+1 counters on all other creatures you control
• Infinite ETB
• Infinite LTB