Union Square will turn into one of the largest outdoor theater venues today for Marvel Comics' first annual Marvelfest.

The event will celebrate the iTunes release of "The Astonishing X-Men" motion comic, and Marvel will premiere the first episode by projecting it three stories high on the facade of the former Virgin Megastore.

"From the outset, we've had one goal: to create a unique event that's a lot of fun for fans while also introducing them to a new form of entertainment," said Mike Pasciullo, Marvel's vice president of merchandising and communication. "This type of launch is a first not only for Marvel, but for the entire comic industry."

Unlike cartoons, a motion comic utilizes the original script and artwork of the comic while adding sound, movement and other effects to enhance the story. In this regard, a motion comic is truer to the original comic than a cartoon.

Forbidden Planet will host three Marvel writers and artists as part of the event.

"It was a natural extension," Forbidden Planet manager Jeff Ayers said. "We're a comic book store a block away, why not team up with us?"

As the event is just a few days before Halloween, Marvel will also hold a costume contest, in which contestants will have the opportunity to be featured in a Marvel comic book.

"It's an awesome way to preview the new 'X-Men' outfits," Forbidden Planet employee Alec Lewellyn said. Lewellyn said he thinks trends will focus on Wolverine outfits based on the movie released earlier this year.

For Pasciullo, Union Square was a choice that reflected the Marvel universe.

"Manhattan isn't just a backdrop in our universe, it's a character in and of itself," he said. "In the end, we realized that there is a real energy and electricity inherent in Union Square."