Galactus is an extraterrestrial that lives on a artifical planet called Taa II. He is known as the planet destroyer because he eats the planets whole. His powers are the Cosmic Energy that is in him. He can take some of his own Cosmic Energy and give it to a living creature and turn him into a herald. He is the enemy to the Fantastic Four and the Silver Surfer.
The Marvel Superhero Saga: Facing Galactus and his Heralds