Mirror Mockery

Official rulings

1. If Mirror Mockery enchants a creature you don’t control, and you are the defending player, you can block with the token. (2015-02-25)
2. If the copied creature is copying something else, then the token enters the battlefield as whatever that creature copied. (2015-02-25)
3. If Mirror Mockery is no longer on the battlefield as its triggered ability resolves, its ability makes a copy of the creature it was enchanting when it left the battlefield. If it left the battlefield because it was no longer enchanting a legal creature, it makes a copy of the creature it was most recently enchanting before it left the battlefield. (2015-02-25)
4. The ability that exiles the token will trigger at end of combat no matter what happens to the original creature or to Mirror Mockery. (2015-02-25)
5. If the copied creature is a token, the token created by Mirror Mockery copies the original characteristics of that token as stated by the effect that put the token onto the battlefield. (2015-02-25)
6. If Mirror Mockery’s ability creates multiple tokens (due to an effect such as the one Doubling Season creates), all such tokens will be exiled by the delayed triggered ability. (2015-02-25)
7. Notably, the token won’t be attacking. (2015-02-25)
8. Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any “as [this permanent] enters the battlefield” or “[this permanent] enters the battlefield with” abilities of the copied creature will also work. (2015-02-25)
9. A token that enters the battlefield as a copy of a face-down creature is a face-up colorless 2/2 creature with no name, abilities, or creature types. (2015-02-25)
10. If the copied creature has {X} in its mana cost, X is considered to be zero. (2015-02-25)
11. The token copies exactly what was printed on the original creature and nothing else (unless that permanent is copying something else or is a token; see below). It doesn’t copy whether that creature 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. (2015-02-25)