Terisian Mindbreaker, and Keening Stone

Prerequisites

• Terisian Mindbreaker on the battlefield
• Keening Stone on the battlefield
• undefined available

Steps

1. Declare Terisian Mindbreaker as an attacker, triggering its ability, causing the defending player to mill half their library, rounded up
2. Activate Keening Stone by paying and tapping it, causing the player to mill cards equal to the number of cards in their graveyard, thus milling the rest of their library

Results

• Infinite mill for target opponent