Comic-Con 2013 is in full swing in San Diego. The biggest nerdgasm of the year boasts plenty of activities and announcements about upcoming movies, games, tv shows, web series, books and, of course, comics.

But half the fun of Comic-Con is the costumes. Cosplay, dressing up, geek Halloween -- whatever you like to call it. Attendees spend the entire year working on their costumes, just to get a chance to parade around as their favorite characters for the weekend.

And some of these costumes are amazing. Whether you like superheroes, zombie survivalists, cartoon mayhem, Disney princesses or sexy femme fatales, every conceivable genre, style and medium is covered. If it has fans, you'll see it walking around in full regalia.

It's a way for costume designers to show off their skills and compete, as well as a nice respite for shy fans to let loose for a few days. And it's clear that many people take their costumes very seriously.

Honestly, it's hard to tell what's professionally done and what isn't, who's a paid actor in official gear and who's a superfan with a great eye for detail. Scroll down to see some of the highlights from the first two days of Comic-Con 2013, and check back soon for more updates.

We'll bring you the most amazing costumes on display, as well as a rundown of the best cosplay babes at the convention. Like what you see? Can you identify your favorite character? Leave and comment below and let us know!