Cast Charismatic Conqueror by paying {1}{W}.
Charismatic Conqueror triggers, causing you and an opponent to copy it.
Resolve the opponent's copy of Charismatic Conqueror, and then resolve your copy of Charismatic Conqueror.
When your Charismatic Conqueror token enters the battlefield,  the opponent's Charismatic Conqueror triggers, causing you to tap your Charismatic Conqueror token.
Resolve the original Charismatic Conqueror spell.
When the nontoken Charismatic Conqueror enters the battlefield, the opponent's Charismatic Conqueror triggers, causing you to not tap the nontoken Charismatic Conqueror, and causing the opponent to create a 1/1 Vampire creature token.
When the opponent's Vampire token enters the battlefield, both Charismatic Conquerors you control trigger, causing you to create at least one 1/1 Vampire creature token.
When your Vampire token enters the battlefield, the opponent's Charismatic Conqueror triggers, causing you to not tap the Vampire token, and causing the opponent to create a 1/1 Vampire creature token.
Repeat from step 7.

Infinite ETB

Infinite creature tokens

Infinite ETB for target opponent

Infinite creature tokens for target opponent

Charismatic Conqueror

Silverquill Lecturer

Cast Phage by paying {3}{B}{B}{B}{B}.
Phage's demonstrate ability triggers, copying the Phage spell and causing an opponent to also copy the Phage spell.
Resolve the opponent's copy of Phage, causing the opponent to create a token copy of it. When the Phage token enters, its first ability triggers, causing its controller to lose the game.

Combos with "Silverquill Lecturer"