Riverchurn Monument + Lord Xander, the Collector

Prerequisites

• Lord Xander does not have summoning sickness.
• You have not activated Riverchurn Monument's exhaust ability.

Steps

1. 1Declare Lord Xander as an attacker, triggering its ability, causing an opponent to mill half their library, rounded down.
2. 2Activate Riverchurn Monument's exhaust ability by paying and tapping it, causing each player to mill cards equal to the number of cards in their graveyard.

Effects

• Infinite mill for target opponent