Isaiah continues speaking to the people of Israel about the evil they do using the metaphors of poisonous snakes and spider's webs. The metaphor here is meant to be emotional, not real: snakes are born alive, not from eggs that are laid.
Eggs of a poisonous snake hatch into more dangerous snakes. "Poisonous snakes" represents evil the people do that harms more and more. Alternate translation: "They make evil that spreads out to make more evil" (See: [[rc://en/ta/man/jit/figs-metaphor]])
This represents the deeds of the people that are useless. Alternate translation: "produce things and activities that are useless" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Eating a poisonous egg will kill the one that eats it and represents self-destruction. Breaking the egg allows the young poisonous snake to hatch and represents spreading destruction. Alternate translation: "The activities they do will destroy them and will spread destruction to others" (See: [[rc://en/ta/man/jit/figs-metaphor]])