If an exiled card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
19-01-2018
wotc
Casting the exiled card follows the normal timing rules for casting that card. For example, if the card is a creature card, you can cast that card only during your main phase while the stack is empty.
19-01-2018
wotc
If you cast a card “without paying its mana cost,” you can’t pay any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, such as that of Silvergill Adept, those must be paid to cast the card.
19-01-2018
wotc
If a token is exiled this way, it can’t be cast.
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.