Cheapest priced copy (Tenth Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Hidden Horror 
Creature — Horror · 4/4 · Uncommon · Salvat 2011 · #73
When this creature enters, sacrifice it unless you discard a creature card.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
6 printings · $0.35 to $2.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Tenth Edition | 149 | Uncommon | $0.35 | $0.49 |
| Classic Sixth Edition | 137 | Uncommon | $0.35 | — |
| Portal Second Age | 75 | Rare | $2.79 | — |
| Premium Deck Series: Graveborn | 2 | Uncommon | — | $0.35 |
| Salvat 2011 | 73 | Uncommon | — | — |
| Weatherlight | 72 | Uncommon | $0.49 | — |
2 rulings from Wizards of the Coast
- 1 April 2008When the ability resolves, you choose whether to sacrifice the creature or perform the other action. If you can’t perform the other action, then you must sacrifice the creature.
- 1 April 2008If the creature is no longer on the battlefield when the ability resolves, you may still perform the action if you want.