So Ouranos didn't like some of his more "monstrous" looking children, as he imprisoned them onto different parts of the Earth because he's a bit of a dick like that. Gaia did NOT like that in the slightest bit. If he wasn't going to take care of his children, he doesn't get to have any MORE.

She created an adamantine sickle out of herself and gave it to Cronus, intended to castrate the sky itself. Although just a boy, he dares to follow through with it. Now he just waits until the night falls again to strike...

"I'm- I'm gonna do it."

He says, sounding confident, despite how funny the situation sounds.