The Mindskinner, and Serra Avatar

Prerequisites

• The Mindskinner on the battlefield
• Serra Avatar on the battlefield
• An opponent cannot block Serra Avatar
• Serra Avatar does not have summoning sickness

Steps

1. Declare Serra Avatar as an attacker
2. When Serra Avatar would deal combat damage to the opponent, The Mindskinner prevents that damage, and causes each opponent to mill that many cards

Results

• Near-infinite mill