Rulings

• 2016-06-08
  If the exiled card has X in its mana cost, you must choose 0 as the value for X when casting it.
• 2016-06-08
  If the imprinted card leaves the exile zone while the activated ability is on the stack, the copy can’t be made.
• 2016-06-08
  If you don’t want to cast the copy, you can choose not to; the copy ceases to exist the next time state-based actions are checked.
• 2016-06-08
  Because you’re already casting the spell using an alternative cost (by casting it without paying its mana cost), you can’t pay any other alternative costs for the card. You can pay additional costs, such as kicker costs. If the card has any mandatory additional costs, you must pay those.
• 2016-06-08
  You cast the copy while the ability is resolving and still on the stack.
• 2017-04-18
  The converted mana cost of a split card is determined by the combined mana cost of its two halves. When you activate the second ability, you may choose to cast either half of the split card, but you may not cast both halves.
• 2016-06-08
  If Isochron Scepter leaves the battlefield while the activated ability is on the stack, the ability can still make a copy.
• 2020-08-07
  If Isochron Scepter leaves the battlefield while the activated ability is on the stack, the ability can still make a copy. On the other hand, if the imprinted card leaves the exile zone while the activated ability is on the stack, the copy can't be made.
• 2020-08-07
  You cast the copy while the ability is resolving and still on the stack. You can't wait to cast it later in the turn.
• 2020-08-07
  If you don't want to cast the copy, you can choose not to; the copy ceases to exist the next time state-based actions are checked.
• 2020-08-07
  If you cast a spell “without paying its mana cost,” you can't choose to cast it for any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, those must be paid to cast the spell.
• 2020-08-07
  If a spell has in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.