Phenax, God of Deception + Sewer Nemesis + Traumatize

Phenax, God of Deception

Sewer Nemesis

Traumatize

How it works

1. Cast Traumatize by paying 3, causing the player named by Sewer Nemesis to mill half their library, rounded down.
2. Activate Sewer Nemesis by tapping it, causing the player to mill cards equal to the cards in their graveyard, likely milling the remainder of their library.