Cast Theoretical Duplication by paying {2}{U}.
Hive Mind triggers, causing each other player to copy Theoretical Duplication.
Resolve all copies of Theoretical Duplication.
Cast Leveler by paying {5}.
Leveler's ETB ability gets put on the stack, followed by each other player's delayed trigger from Theoretical Duplication.
Resolve one of these Theoretical Duplication abilities, creating a token copy of Leveler under another player's control.
That player's Leveler's ETB ability triggers, exiling that player's library.
Repeat the previous two steps for each other player.
Your own Leveler's ETB ability resolves, exiling your library.
Each opponent will lose the game in their draw step for failing to draw from an empty library.

Exile all libraries

Hive Mind

Leveler

Theoretical Duplication

Cast Theoretical Duplication by paying {2}{U}.
Hive Mind triggers, causing all opponent to copy Theoretical Duplication.
Resolve each Theoretical Duplication, causing all players to create a token of all creatures that enter the battlefield under an opponent's control this turn.
Cast Phage by paying {3}{B}{B}{B}{B}.
Each opponent's Theoretical Duplication triggers.
Resolve the first Theoretical Duplication trigger, causing the opponent to create a token copy of Phage.
The Phage token enters the battlefield, causing its controller to lose the game.
Repeat from step 6 for each remaining trigger.

Combos with "Theoretical Duplication"