Fans by the tens of thousands are expected to funnel through the aisles of the San Diego Convention Center between Thursday and Sunday.
Stan Lee, now chairman emeritus at Marvel Comics, marvels himself at how much this colorful gathering has grown.
"When the first Comic-Con started a million years ago, it might have been a dozen people in a cellar somewhere," said Lee. "All of a sudden it is over 150,000 people."
And a good portion of those thousands of people come to Comic-Con to snag autographs.
But for others, it's all about getting into character. Some are a little wild, some are really creepy, and some are more elaborate than others.
"I like being in a building with 180,000 people that are just as passionate as me about this stuff," said G4 correspondent Blair Herter. "Aren't afraid to wear their underwear on the outside to show that they have Green Lantern on their crotch, because nobody judges here and that's fantastic."
One bit of news out of Comic-Con on Thursday is Popeye will be returning as a monthly comic next year.