Mirrorform

If the copied permanent is copying something else, then the permanents become copies of whatever that permanent copied.

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.

If the copied permanent has X generic mana in its mana cost, X is 0.