Cheapest priced copy (Conspiracy: Take the Crown): $0.35 at Card Kingdom, near mint, their price list as of .
Copperhorn Scout 
Creature — Elf Scout · 1/1 · Common · Conspiracy: Take the Crown · #179
Whenever this creature attacks, untap each other creature you control.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
3 printings · $0.35 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Conspiracy: Take the Crown | 179 | Common | $0.35 | $2.49 |
| Conspiracy | 160 | Common | $0.35 | $1.99 |
| Scars of Mirrodin | 116 | Common | $0.35 | $4.49 |
2 rulings from Wizards of the Coast
- 1 January 2011Untapping an attacking creature doesn’t cause it to stop attacking.
- 1 January 2011As Copperhorn Scout’s ability resolves, you’ll untap each other creature you control regardless of whether that creature was attacking.