If the chosen creature is a token, Stunt Double copies the original characteristics of that token as stated by the effect that put the token onto the battlefield. Stunt Double isn’t a token.
23-08-2016
wotc
If the copied creature has {X} in its mana cost, that X is considered to be 0.
23-08-2016
wotc
Any enters-the-battlefield abilities of the copied creature will trigger when Stunt Double enters the battlefield. Any “as [this creature] enters the battlefield” or “[this creature] enters the battlefield with” abilities of the chosen creature will also work.
23-08-2016
wotc
Stunt Double copies exactly what was printed on the original creature (unless that creature 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 any Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, or so on.
23-08-2016
wotc
If Stunt Double somehow enters the battlefield at the same time as another creature, it can’t become a copy of that creature. You may choose only a creature that’s already on the battlefield.
23-08-2016
wotc
You can choose not to copy anything. In that case, Stunt Double enters the battlefield as a 0/0 creature, and is put into the graveyard immediately (unless something else is raising its toughness).
23-08-2016
wotc
If the chosen creature is copying something else (for example, if the chosen creature is another Stunt Double), then Stunt Double enters the battlefield as whatever the chosen creature copied.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.