Triskaidekaphobia

• WWizards of the Coast2025-01-24
  Official Ruling
  If each player has 13 life as Triskaidekaphobia’s ability resolves, the game ends in a draw.
• WWizards of the Coast2025-01-24
  Official Ruling
  You choose one of the modes even if no player will lose the game. Players will still gain or lose life as appropriate.
• WWizards of the Coast2025-01-24
  Official Ruling
  In a Two-Headed Giant game, each team with 13 life loses the game, then each player on each team gains or loses 1 life, causing the team’s life total to go up or down by 2.
• WWizards of the Coast2025-01-24
  Official Ruling
  If you choose Triskaidekaphobia’s second mode and begin to resolve it while an opponent’s life total is 13 and your life total is 1, that opponent will lose the game before you lose 1 life.

Rulings via Scryfall