At the beginning of your end step, Jon Irenicus triggers, giving control of Giant Shark to an opponent who controls no Islands.
When Giant Shark's controller controls no Islands, Giant Shark triggers, causing them to sacrifice it.
However, Giant Shark cannot be sacrificed due to its ability.
Giant Shark triggers again, creating a mandatory infinite loop that causes the game to end in a draw.

Draw the game

Jon Irenicus, Shattered One

Giant Shark

If needed, give control of Giant Shark to an opponent who controls no Islands.
When Giant Shark's controller controls no Islands, Giant Shark triggers, causing them to sacrifice it.
However, Giant Shark cannot be sacrificed due to Assault Suit.
Giant Shark triggers again, creating a mandatory infinite loop that causes the game to end in a draw.

Combos with "Giant Shark"