Cast Rot Hulk by paying {5}{B}{B}.
When Rot Hulk enters, it and Necroduality trigger.
Resolve the Rot Hulk trigger, returning Rot-Tide Gargantua from your graveyard to the battlefield.
When Rot-Tide Gargantua enters, it and Necroduality trigger.
Resolve the Rot-Tide Gargantua trigger, sacrificing it.
When Rot-Tide Gargantua is exploited, Rot-Tide Gargantua triggers, causing each opponent to sacrifice a creature.
Resolve the Necroduality trigger, creating a token copy of Rot-Tide Gargantua.
When the token Rot-Tide Gargantua enters, it triggers, sacrificing Rot Hulk.
When Rot Hulk is exploited, Rot-Tide Gargantua triggers, causing each opponent to sacrifice a creature.
Resolve the Necroduality trigger from step 2, creating a token copy of Rot Hulk.
When the token Rot Hulk enters, it triggers, returning Rot Hulk from your graveyard to the battlefield.
Repeat from step 2.

Each opponent sacrifices all creatures they control

Infinite creature ETB

Infinite creature LTB

Infinite creature tokens

Infinite death triggers

Infinite creature sacrifice triggers

Return some creature cards from your graveyard to the battlefield

Necroduality

Rot Hulk

Rot-Tide Gargantua

Cast Rot-Tide Gargantua by paying its mana cost.
When Rot-Tide Gargantua enters, its exploit ability triggers, causing you to sacrifice it.
When Rot-Tide Gargantua dies, its second ability and Ratadrabik trigger.
Resolve the Rot-Tide Gargantua trigger, causing each opponent to sacrifice a creature.
Resolve the Ratadrabik trigger, creating a token copy of Rot-Tide Gargantua that is a 2/2 legendary Zombie in addition to its other types.
Repeat from step 2 using the Rot-Tide Gargantua token instead.

Ratadrabik of Urborg

Leyline of Singularity

Cast Rot-Tide Gargantua by paying {0}.
When Rot-Tide Gargantua enters the battlefield, it triggers, causing you to sacrifice it.
When Rot-Tide Gargantua dies, Enduring Renewal triggers, returning it to your hand from your graveyard.
Repeat.

Infinite storm count

Rooftop Storm

Enduring Renewal

Cast Rot-Tide Gargantua either from your hand or from the top of your library by paying {0}.
When Rot-Tide Gargantua enters the battlefield, its exploit ability triggers, causing you to sacrifice it.
When Rot-Tide Gargantua dies, Mortuary triggers, putting it on top of your library from your graveyard.
Repeat.

Mortuary

Realmwalker

Combos with "Rot-Tide Gargantua"