Spellstutter Sprite

Flash
Flying
When Spellstutter Sprite enters, counter target spell with mana value X or less, where X is the number of Faeries you control.

The List

Jumpstart 2022

Flash
Flying
When Spellstutter Sprite enters the battlefield, counter target spell with mana value X or less, where X is the number of Faeries you control.

Secret Lair Drop

Modern Masters

Flash
Flying
When Spellstutter Sprite enters the battlefield, counter target spell with converted mana cost X or less, where X is the number of Faeries you control.

Magic Online Promos

The value of X needs to be determined both when the ability triggers (so you can choose a target) and again when the ability resolves (to check if that target is still legal). If the number of Faeries you control has decreased enough in that time to make the target illegal, Spellstutter Sprite’s ability won’t resolve (and the targeted spell will resolve as normal).