Fireball | Magic: The Gathering
Formats Fireball is Legal in
Official Oracle Text for Fireball
Fireball costs more to cast for each target beyond the first.
Official Rulings for Fireball
12/1/2004 : If, for example, X is 5 and you choose three target creatures, Fireball has a total cost of (even though its mana cost is just ). If those creatures are all still legal targets as Fireball resolves, it deals 1 damage to each of them.
5/1/2009 : You may cast Fireball with zero targets, regardless of the value chosen for X. If you do so, it will not be a targeted spell, and no damage will actually be dealt when it resolves.
10/1/2009 : Fireball's damage is divided as Fireball resolves, not as it's cast, because there are no choices involved. The division involves only targets that are still legal at that time.
10/1/2009 : You can target more than X creatures. However, if the number of legal targets at the time Fireball resolves is greater than X, none of them will be dealt any damage.