So, it eats those who consumed The Peach. If correct, I'm seeing the similar action as Kaguya from Naruto. That 'egg' absorbs life to grant power to others.
No, dont fall into the trap of "leaving one alive" etc! Wipe them all out! Have you people never seen these tropes? You dont leave your enemies alive, or kids of your enemies etc, you destroy them all, check the remains then feed their ashes into the heart of the sun!