Hecatomb 
Enchantment
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.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL