Assault Suit, and Bog Serpent

Prerequisites

• Assault Suit on the battlefield
• Bog Serpent on the battlefield
• Assault Suit attached to Bog Serpent
• A player controls no Swamps

Steps

1. If necessary, at the beginning of the upkeep of an opponent who controls no Swamps, Assault Suit triggers, causing that player to gain control of Bog Serpent and untap it
2. Bog Serpent triggers, but cannot be sacrificed due to Assault Suit's ability
3. Step 2 repeats forever, resulting in a mandatory infinite loop that causes the game to end in a draw

Results

• Draw the game