Mirror March
Enchantment
Whenever a nontoken creature enters the battlefield under your control, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.
Illustrated by
Ravnica Allegiance Promos#108sRareEnglishLegality
Rulings
All of the tokens enter the battlefield at the same time.
Each token copies exactly what is printed on the creature and nothing else (unless that creature is copying something else; see below). It doesn’t copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.
If the copied creature is copying something else, each token enters the battlefield as whatever that creature is copying.
If the copied creature has 
in its mana cost, X is 0.
If the entering creature leaves the battlefield before Mirror March’s ability resolves, use that creature’s last known existence on the battlefield to determine the token’s characteristics.
Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any “As [this creature] enters the battlefield” or “[This creature] enters the battlefield with” abilities of the copied creature will also work.