Phenax, God of Deception + The Walls of Ba Sing Se + Crab Umbra Combo

All permanents on the battlefield (The Walls of Ba Sing Se without summoning sickness on the battlefield and Crab Umbra attached to The Walls of Ba Sing Se on the battlefield).

at least available

Activate The Walls of Ba Sing Se by tapping it, causing a player to mill thirty cards.

Activate Crab Umbra by paying , untapping The Walls of Ba Sing Se.

Repeat as mana allows.

Significant mill

Significant self-mill