Galactus

Galactus is a godlike supervillain from Marvel comics who although not exactly malevolent is nevertheless a dangerous individual who requires nothing short of entire worlds to hold off his eternal hunger and is also linked in such a way to the Marvel universe so that if he dies the entire Marvel universe will end.. this makes Galactus somewhat unique in the fact he is both an immensely destructive force yet also necessary for the existence of the universe.

Born before the current Marvel universe came to be the young Galactus escaped death when his universe came to an end via merging with the Cosmic-Egg - resulting in him being reborn into the new infant universe as the mighty Galactus - devourer of worlds.. as time went by Galactus would create numerous Heralds to seek out suitable worlds for him to devour, the most famous of his many Heralds was the Silver Surfer - who would rebel against Galactus in defence of the Earth and be replaced by Nova.

Galactus seems to prefer planets that are inhabited, or at the very least suitable for life, this trait only serves to make him more villainious as his endless hunger has cost the lifes of millions - if not billions as well as rendering even more homeless and scattered across the universe (as was the case when he famously devoured the Skrull home-world, causing the once powerful Skrull Empire to disperse into the stars).

Too powerful to be defeated by any one hero Galactus is often portrayed as a force rather than a being, a destructive god who thinks nothing of pitiful pleas for mercy or compassion yet also seems to be driven by a deeper understanding of the universe than mortals - as he once stated he is ultimately destined to give much more than he has taken from the universe.

It has also been revealed that Galactus is the only thing stopping the spirit of destruction known as Abraxas from being released into the universe - so in many ways the Marvel universe is lucky to have Galactus around..

Of course none of this means much to those caught in the path of a hungry Galactus and for many the towering figure of Galactus is the final image they will ever see as their world is consumed by an unimaginable force of power - perhaps this is what truly makes Galactus so terrifying.. he is not evil, he can not be bribed nor reasoned with.. he simply is.