Cheapest priced copy (Classic Sixth Edition): $0.49 at Card Kingdom, near mint, their price list as of .
Hecatomb 
Enchantment · Rare · Classic Sixth Edition · #136
When this enchantment enters, sacrifice this enchantment unless you sacrifice four creatures.
Tap an untapped Swamp you control: This enchantment deals 1 damage to any target.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $1.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fifth Edition | 167 | Rare | $0.59 | — |
| Classic Sixth Edition | 136 | Rare | $0.49 | — |
| Ice Age | 130 | Rare | $1.29 | — |
3 rulings from Wizards of the Coast
- 4 October 2004If you have less than 4 creatures, you do not partially sacrifice. You pay 4 creatures or none.
- 4 October 2004The sacrifice is done as a triggered ability just after it enters. It is not done on casting.
- 4 October 2004You choose whether to sacrifice creatures or not on resolution. If not, then you sacrifice Hecatomb. You can choose to not sacrifice creatures if you no longer control this card on resolution.