Arwen, Weaver of Hope, Watchful Radstag, and Elegant Entourage

Prerequisites

• Arwen, Weaver of Hope on the battlefield
• Watchful Radstag on the battlefield
• Elegant Entourage in hand
• available

Steps

1. Cast Elegant Entourage by paying
2. It'll enter with a number of +1/+1 counters due to Arwen
3. When Elegant Entourage enters, Watchful Radstag's evolve ability triggers, putting a +1/+1 counter on it
4. Watchful Radstag's second ability triggers, creating a token copy of it
5. It'll enter with a number of +1/+1 counters due to Arwen
6. When the token Watchful Radstag enters, the nontoken Watchful Radstag's evolve ability and Elegant Entourage trigger
7. Resolve the Elegant Entourage trigger, giving Arwen +1/+1 until end of turn
8. Resolve the Watchful Radstag trigger, putting a +1/+1 counter on it
9. Repeat from step 3

Results

• Infinite +1/+1 counters on most creatures you control
• Infinite ETB
• Infinite creature tokens