Mirrorform

• WWizards of the Coast2025-11-17
  Official Ruling
  The permanents copy exactly what was printed on the original permanent and nothing else (unless that permanent is copying something else; see below). They don't copy whether that permanent is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, and so on.
• WWizards of the Coast2025-11-17
  Official Ruling
  If the copied permanent is copying something else, then the permanents become copies of whatever that permanent copied.
• WWizards of the Coast2025-11-17
  Official Ruling
  Because the permanents aren't entering the battlefield when they become copies of the target permanent, any "When [this permanent] enters" or "[This permanent] enters with" abilities of the copied permanent won't apply.
• WWizards of the Coast2025-11-17
  Official Ruling
  If the copied permanent has in its mana cost, X is 0.

Rulings via Scryfall