Ith, High Arcanist, and Mesmeric Orb

Prerequisites

• Ith, High Arcanist on the battlefield
• Mesmeric Orb on the battlefield
• Ith does not have summoning sickness

Steps

1. Declare Ith as an attacker
2. Activate Ith by tapping it, untapping Ith and preventing all combat damage that would be dealt to or dealt by it this turn
3. Mesmeric Orb triggers, causing you to mill a card
4. Repeat from step 2

Results

• Infinite self-mill