Before the Sixth Edition rules update, this was an official game term, but it has since become slang. Prior to the release of Dominaria, the rules said that a spell was "countered on resolution" if it had no legal targets at the time it would resolve, but under current rules the spell simply "doesn't resolve".
R&D considers the rule that spells with a target that do other things and don't have those other things happen if the target gets removed to be very unintuitive. It, however, has proven to be a tricky issue to solve.
- 608.2b If the spell or ability specifies targets, it checks whether the targets are still legal. A target that’s no longer in the zone it was in when it was targeted is illegal. Other changes to the game state may cause a target to no longer be legal; for example, its characteristics may have changed or an effect may have changed the text of the spell. If the source of an ability has left the zone it was in, its last known information is used during this process. If all its targets, for every instance of the word “target,” are now illegal, the spell or ability doesn’t resolve. It’s removed from the stack and, if it’s a spell, put into its owner’s graveyard. Otherwise, the spell or ability will resolve normally. Illegal targets, if any, won’t be affected by parts of a resolving spell’s effect for which they’re illegal. Other parts of the effect for which those targets are not illegal may still affect them. If the spell or ability creates any continuous effects that affect game rules (see rule 613.11), those effects don’t apply to illegal targets. If part of the effect requires information about an illegal target, it fails to determine any such information. Any part of the effect that requires that information won’t happen.
Example: Sorin’s Thirst is a black instant that reads, “Sorin’s Thirst deals 2 damage to target creature and you gain 2 life.” If the creature isn’t a legal target during the resolution of Sorin’s Thirst (say, if the creature has gained protection from black or left the battlefield), then Sorin’s Thirst doesn’t resolve. Its controller doesn’t gain any life.
Example: Plague Spores reads, “Destroy target nonblack creature and target land. They can’t be regenerated.” Suppose the same creature land is chosen both as the nonblack creature and as the land, and the color of the creature land is changed to black before Plague Spores resolves. Plague Spores still resolves because the black creature land is still a legal target for the “target land” part of the spell. The “destroy target nonblack creature” part of the spell won’t affect that permanent, but the “destroy target land” part of the spell will still destroy it. It can’t be regenerated.
- Mark Rosewater (December 19, 2016). "'Fizzle' is a deprecated term and we should use "Countered on resolution" instead.". Blogatog. Tumblr.
- Eli Shiffrin (April 13, 2018). "Dominaria Comprehensive Rules Changes". magicthegathering.com. Wizards of the Coast.
- Mark Rosewater (October 06, 2015). "One of the hardest things for new players is the idea of a spell fizzling out when the target is sacrificed.". Blogatog. Tumblr.
- Mark Rosewater (January 26, 2015). "What would happen then if the spell didn't fizzle?". Blogatog. Tumblr.
- Mark Rosewater (December 30, 2015). "What do you think is wrong with spells fizzling?". Blogatog. Tumblr.
- Mark Rosewater (May 29, 2017). "Has R&D considered getting rid of "fizzling"?". Blogatog. Tumblr.
- Mark Rosewater (August 27, 2017). "Do you think spells "fizzling" (ie being countered on resolution because of an invalid target) will ever be removed from the rules?". Blogatog. Tumblr.