Cheapest priced copy (Tarkir: Dragonstorm): $0.35 at Card Kingdom, near mint, their price list as of .
Formation Breaker 
Creature — Beast · 2/1 · Uncommon · Tarkir: Dragonstorm · #143
Creatures with power less than this creature's power can't block it.
As long as you control a creature with a counter on it, this creature gets +1/+2.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Tarkir: Dragonstorm | 143 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 4 April 2025You compare Formation Breaker’s power to the power of any creature trying to block it only as blockers are declared. Once Formation Breaker has been legally blocked by a creature, changing the power of either creature won’t change or undo the block.