Zochra, Horror in the Sky?

Emerge {5}{u}{b}{g} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's converted mana cost.)
Whenever you emerge a creature, create two 1/1 colorless eldrazi scion creature tokens into play. They have "Sacrifice this creature: Add {c} to your mana pool." ({c} represents colorless mana.)
Whenever Zochra, Horror in the Sky? attacks, defending player sacrifices two creatures.