Noble Ox

• WOTC Official Reminder Textofficial rules
  Flash — You may cast this spell any time you could cast an instant.

• WWizards of the Coast2024-11-08
  Official Ruling
  Noble Ox’s enters-the-battlefield ability causes all unblocked creatures attacking you to become blocked by Noble Ox, regardless of whether Noble Ox can normally block that creature.
• WWizards of the Coast2024-11-08
  Official Ruling
  Playtest cards use a modified version of game symbols, such as and . These modified symbols should be treated as the standard symbols during play.
• WWizards of the Coast2024-11-08
  Official Ruling
  Make sure to enunciate when you cast this.
• WWizards of the Coast2024-11-08
  Official Ruling
  Attacking creatures are only considered unblocked after blockers have been declared. Before then, attacking creatures are neither blocked nor unblocked.
• WWizards of the Coast2024-11-08
  Official Ruling
  For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure.
• WWizards of the Coast2024-11-08
  Official Ruling
  Playtest cards aren’t legal for play in any tournament format other than Mystery Booster Limited formats. On the other hand, we expect they will spice up a wide variety of non-tournament games (as long as everyone’s on the same page about using them!).

Rulings via Scryfall