Biorhythm

• WWizards of the Coast2004-10-04
  Official Ruling
  If a player controls no creatures when this resolves, their life total will become zero and they will lose the game.
• WWizards of the Coast2004-10-04
  Official Ruling
  This spell causes the player to lose or gain enough life to change to the new life total.

Rulings via Scryfall

• WO
  Wizards of the Coast2026-02-09

  Biorhythm was unbanned in commander on February 9, 2026. While Biorhythm is stronger, easier to set up, and, yes, can make the game unsatisfyingly end, it takes enough setup and has enough counterplay that it's far from an auto-include. As a situational eight-mana sorcery, there are plenty of times where it's a weak draw. We accept there is some risk here, but it's also a card with big moments that will generate some excitement. Source: https://magic.wizards.com/en/news/announcements/commander-banned-and-restricted-february-9-2026