Cheapest priced copy (Ultimate Masters): $15.99 at Card Kingdom, near mint, their price list as of .
Disrupting Shoal 
Instant — Arcane · Rare · Betrayers of Kamigawa · #33
You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost.
Counter target spell if its mana value is X.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $15.99 to $399.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Betrayers of Kamigawa | 33 | Rare | $19.99 | $399.99Out of stock |
| Ultimate Masters | 51 | Rare | $15.99 | $59.99 |
3 rulings from Wizards of the Coast
- 1 February 2005Disrupting Shoal can target any spell, but does nothing unless that spell's mana value is X.
- 7 December 2018If a card in your hand has {X} in its mana cost, X is considered to be 0.
- 7 December 2018If a spell has {X} in its mana cost, include the value chosen for that X when determining the mana value of that spell, even if it was cast for an alternative cost and no mana was spent on X.