Ashaya, Soul of the Wild, Arbor Elf, and Mesmeric Orb

Prerequisites

• Ashaya, Soul of the Wild on the battlefield
• Arbor Elf on the battlefield
• Mesmeric Orb on the battlefield
• Arbor Elf does not have summoning sickness

Steps

1. Activate Arbor Elf by tapping it, untapping itself
2. Mesmeric Orb triggers, causing you to mill a card
3. Repeat

Results

• Infinite self-mill