When Elite Arcanist enters, you may exile an instant card from your hand. , : Copy the exiled card. You may cast the copy without paying its mana cost. X is the mana value of the exiled card.
If the exiled card is a split card, then X is determined by the combined mana cost of both halves. However, when you cast the copy, you choose only one half to cast. You may cast a different half each time you create and cast a copy.
01-07-2013
wotc
If the copied card has {X} in its mana cost, you must choose 0 as its value when casting the copy. Don't confuse that {X} with the {X} in the activation cost of Elite Arcanist's ability.
01-07-2013
wotc
The copy is created in and cast from exile. You must still follow any timing restrictions, such as "Cast [this spell] only during combat."
01-07-2013
wotc
If Elite Arcanist leaves the battlefield, you will no longer be able to copy the exiled card. If it returns to the battlefield, you'll be able to exile another instant card from your hand, but Elite Arcanist will be a different permanent with no connection to the first exiled card.
01-07-2013
wotc
You don't choose the value of {X} in the activation cost of Elite Arcanist's ability. It's defined by the mana value of the exiled instant card.
01-07-2013
wotc
You can't pay any alternative costs such as overload costs. You can pay additional costs such as kicker costs. If the spell has any mandatory additional costs, you must pay those.
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.