Actually, Silver Surfer is the good guy, sort of...
He was a scientist that came from the planet Zenn-La. And then one day, along came big bad wolfGalactus the World Devourer to his planet. So Galactus huff and puff and threaten to eat the planet Zenn-La. Why, you say? Because he can.
So, to save his homeworld from being Galactus' lunch, Norin Radd offered himself to be a Herald of Galactus. A herald's job is awesome. You got this enormous power given by Galactus called the Power Cosmic and a great looking surfboard and one of a kind silver skin. Thus he's named the Silver Surfer (insert loud echoes here).
As for the story in Fantastic Four 2.... you'll just have to see it for yourself
Just a clue, it came from an old Fantastic Four storyline titled "The Coming of Galactus" back in 1966.
Somebody convinced me that th epic movie was good so i intend to get it online.
But i think and hope that is not the case for F4. This week there is supposed to be Ghost Rider, and along the way spiderman, Teenage Mutant Ninja turtles, Rush hour, Harry potter (?), etc etc. There are too many blockbusters on the way.