Who do you think is the most powerful fictional villain ever?

Shuma Gorath, he rules 100 dimensions, his very presence in our universe could destroy it that's why he can't fully manifest himself here, our universe can't support his kind of power! He made a Vooddoo doll of the entire Earth for god's sake who can do that? Only Dr. Strange can beat Shuma Gorath, but of course Dr. Strange can beat any villain from Marvel :)

Gotta go with Galactus.

Omnicron was defeated by a small band of transformers. They crashed through his eye like it was glass. Galactus would turn Omnicron into his portable toilet.

Those guys turn into planets? Well these guys have galaxies as their energy source.

The Anti-Spiral from Gurren Lagann

Pic: http://animanachronism.files.wordpress.com/2008/07...

http://s728.photobucket.com/albums/ww283/arcsparta...

His opponent the Tengenn Toppa Gurren Lagann

Pic: http://media.photobucket.com/image/Grand%20Zamboa%...

Phisically? Galactus from the silver surfer stuff. The guy eats planets for christ sake!

Unicron - Transformers

able to transform into a mechanical planet. He travels the galaxy, seeking worlds to consume for nourishment

Take that galactus, not only he consumes it he also transforms into one.

tom in "tom and jerry"

because whatever bad happens to tom, he will not die...

he may also become a protagonist...