Let's harness its energy!

touché.

I actually remember a SF short story where astronomers detected something looking like a giant bird coming from outer space into the solar system. It then approached Mars, the planet cracked open and a baby bird came out. Next, both birds started heading for Earth... and people started drilling in a desperate attempt to kill whatever was under their feet...

Unfortunately I don't remember the author.

Marvels' Celestials also have this story:

"Celestial Eggs within planets

It was stated by the Celestial Madonna that Earth and many other worlds were implanted with a Celestial Egg/Embryo at their center, gestating for millions of years before birthing and consuming the planet. Similar processes was witnessed in Earth-9997 and other realities."

https://marvel.fandom.com/wiki/Celestials_(Race)#Celestial_E...