Escaped The Underdark

Other commander permanents you control have "Whenever you Venture Into The Dungeon, you
may change the room text to; Each opponent
loses 1 life & you gain 1 life" Only once per turn.
{4}: Venture Into The Dungeon. If you control
your Commander &/or you are the Monarch
this effect cost {1} less. Only usable once per turn.
It's {1} less for each differently named dungeon
you've completed.