Activate Volrath's Dungeon's second ability by discarding Dakmor Salvage.
The Gitrog Monster's third ability triggers, causing you to mill two cards and return Dakmor Salvage from your graveyard to your hand.
Resolve the Volrath's Dungeon ability, causing target player to put a card from their hand on top of their library.
Repeat.

Infinite self-mill

Near-infinite self-discard triggers

The Gitrog Monster

Dakmor Salvage

Volrath's Dungeon

Cast Volrath's Dungeon for {2}{B}{B}.
Target the opponent who's turn is after yours with Mindslaver.
On their turn, force them to pay 5 life to destroy Volrath's Dungeon while holding priority.
With the destroy trigger on the stack, repeat this process until they have 0 life.

Combos with "Volrath's Dungeon"