Cheapest priced copy (Ravnica: Clue Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Battlefront Krushok 
Creature — Beast · 3/4 · Uncommon · Fate Reforged · #125
This creature can't be blocked by more than one creature.
Each creature you control with a +1/+1 counter on it can't be blocked by more than one creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica: Clue Edition | 157 | Uncommon | $0.35 | — |
| Fate Reforged | 125 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 24 November 2014The second ability applies only as blockers are declared. If a creature you control with no +1/+1 counters on it becomes blocked by more than one creature, putting a +1/+1 counter on it won’t change or undo the block.