u/InfamousAdvisor9286

If I cast a spell like Writhing Chrysalis, which has "when you cast this spell, create two 0/1 colorless eldrazi spawn creature tokens with "sacrifice this creature: add {C}""

Since it's activated ability goes onto the stack after the spell, and those creatures are created before it's cost must be paid, could I use the spawns to pay it's mana cost?

Consequently, as if the cost cannot be paid, the game​ rewinds, would the spell Kozilek, the broken reality" be used to check the top card of my library for free?