When you're making a film in which a squad of monsters goes monstero-a-monstero against a gaggle of aliens, Monsters vs. Aliens would seem to be a natural title. And yet Rob Letterman and Conrad Vernon, the directors of DreamWorks Animation and Paramount's newest CGI-animated blockbuster, struggled to come up with a name for their dead-on spoof of—and loving homage to—the creature features of yesteryear.

"We have a secret list of alternate titles that includes some of the most ridiculous names ever," reveals Letterman. "Conrad came up with Ordinary Monsters at one point—that was going to be the art-house version." Vernon ticks off a few more rejected titles: "Freak Squad, The Thing What Hid in the Hole." Eventually the duo came to their senses and christened the film Monsters vs. Aliens, a name that not only accurately reflects the movie's content, but also grabs the immediate attention of its target audience: sci-fi geeks and the friends and family members who love them. "I think the 'Vs.' is what gets the fanboys—and we're among them," Vernon says, chuckling.

Like all monster-movie-loving nerds, Letterman and Vernon had dreamed of seeing their favorite creatures square off against their favorite extraterrestrials when they were still in rocketship pajamas. ("We had this idea when we came out of the womb," Letterman jokes, "I came out with monsters and Conrad came out with aliens.") But the specific idea that became Monsters vs. Aliens didn't really take shape until both men were all grown up and working at DreamWorks Animation, where they steadily moved up the ladder from artists to directors. (Vernon made his feature debut on 2004's Shrek 2 while Letterman co-helmed Shark Tale, released later that same year.)

At one point, Vernon came across an unproduced script entitled Rex Havoc, which was based on an obscure comic book and starred a motley crew of bizarre monsters. "I thought it would be interesting to do a '50s-style B-movie in animation and Rob wanted to do a Dirty Dozen-type action film. So we threw those ideas together and it came out as Monsters vs. Aliens."
From the moment they sat down to plot out the film's story, Vernon and Letterman knew that their take on monsters would depart significantly from the '50s films that they grew up watching. "Those B-movie monsters never had any personality or character," Letterman explains. "They were literally these cardboard things. So our conceit for Monsters vs. Aliens was to give those classic monsters personality and make them the good guys.

"For example, the movie is called The Creature from the Black Lagoon," continues Vernon. "But you don't know what he's like, what he wants, what his hopes and dreams are. All you know is that he's in love with this woman and I wanted to get more into that story." With that approach in mind, the directors, who both receive a "story by" credit on the film (Letterman also numbers among the movie's five credited screenwriters), devised a plot that gives audiences plenty of time to get to know and, more importantly, like the movie's collection of monsters.

Our gateway into the story is Susan Murphy (voiced by Reese Witherspoon), an ordinary small-town girl who is preparing to walk down the aisle to marry her career-minded fiancé when a chance encounter with a glowing meteorite suddenly adds 50 feet to her 5-ft., 6-inch frame. The confused giantess is promptly captured by the military, who rename her Ginormica and lock her away in a high-tech prison populated by other creatures, including B.O.B. (Seth Rogen), a slow-witted blob; The Missing Link (Will Arnett) a monster that's part man, part fish, part ape...but all jock; Dr. Cockroach (Hugh Laurie), a mad scientist whose risky experiments have left him with the mind of a genius and the body of a cockroach; and, finally, Insectosaurus, a towering insect with Godzilla's bulk and Totoro's gentle disposition.

Locked up for decades under the watchful eye of General W.R. Monger (Kiefer Sutherland, doing his best George C. Scott impression), Susan's new friends have given up hope of ever seeing daylight again, but she still dreams of returning to the life she lost. That opportunity arises when an alien who calls himself—er, make that itself—Gallaxhar (Rainn Wilson) arrives on Earth searching for the glowing substance that transformed Susan into Ginormica. Conventional weapons are useless in the face of this otherworldly menace, so, on the advice of General Monger, the President (Stephen Colbert) offers the monsters a deal: Defeat the alien and win your freedom. Lose...and there probably won't be much of a planet left anyway.

After briefly toying with the idea of incorporating actual iconic monsters into their film, Vernon and Letterman decided it would be a wiser choice to create new creatures from the webbed feet up. "There's a certain narrative you have to stick true to if you actually use the monsters from those '50s movies," Vernon explains. "Ultimately we decided that we'd rather base our characters on older monsters than use them. It was just more fun to make up our own versions."

That said, eagle-eyed fans will be able to spot numerous visual and verbal references to classic creature features littered throughout Monsters vs. Aliens. A shot of B.O.B.'s "birth," for example, is almost identical to a scene in the horror classic The Blob. (Additionally, B.O.B. was captured by the government in 1958—the same year that The Blob premiered in theatres.) Gallaxhar's sequin outfit, meanwhile, was inspired by similar extraterrestrial clothing seen in the 1968 cult classic Destroy All Monsters, which Letterman and Vernon both single out as a particular favorite.



Of course, you don't have to be a monster-movie expert to get the majority of the film's jokes, which include a healthy mixture of crowd-pleasing pratfalls and clever one-liners. And because the movie is called Monsters vs. Aliens, there's plenty of action as well, including a lengthy rumble on the streets of San Francisco that leaves the beautiful Bay Area almost in ruins and a breathless climax set aboard Gallaxhar's ship. The directors are particularly proud of the San Francisco battle, which features such eye-popping moments as Insectosaurus struggling to keep the Golden Gate Bridge aloft and Ginormica using a pair of empty cars as roller skates to speed down the city's steep hills.

"That sequence took almost two years," Letterman says. "We were constantly going in and refining it, putting in amazing action bits and making sure the characters' personalities and the comedy were still there. When we first started planning the movie, we planted a stake in the ground and said, 'All our action scenes will be character-driven.' And our action sequences are as epic as we can possibly make them by using all the greatest tools and technologies. But they are always told through the characters' point of view. That's the best kind of action for us."

Of the many tools and technologies that Letterman and Vernon employed to bring their vision to life, the most important has to be InTru 3D, a new form of 3D technology developed by Intel that gives animators more options for designing 3D images, while also creating a more immersive experience (with less eyestrain) for viewers watching the film in theatres. Starting with Monsters vs. Aliens, all DreamWorks animated features will be produced using the InTru 3D process. While the directors admit that being the pioneers of this new technology was daunting at first ("We were thinking, 'What if it’s like a horror movie with viewers running out of the theatre with bloody eyes?'" Vernon says, laughing), a field trip to James Cameron's studio, where the forward-thinking director is currently making his own 3D film, the highly anticipated Avatar, helped put their minds at ease.

"Everyone who is currently making 3D movies has been very open about sharing information about how to do things, because they all want this technology to work out," says Letterman. "Jon Landau [Cameron's producer] shared with us that Cameron's approach is just to tell your story, make your movie and things will work out. From that point forward, working in 3D became very natural. And right up front, we made a steadfast rule: 'Let's not poke people in the eyeballs with this thing.' It's not a gimmick, it's a new storytelling tool, just like color, sound and everything that came before. To be fair, we broke that rule once or twice for joke reasons, but if we're going to respect 3D as a medium, we knew we couldn't just do gimmicky shots. In many ways, it made total sense to make this particular movie in 3D, considering the title and the genre we were having fun with. There's no way it would be as cool in 2D."

Having finally realized their childhood dreams of watching monsters battle aliens, Letterman and Vernon are now embarking on a whole new adventure: live-action filmmaking. Letterman is currently helming an effects-laden version of the classic 18th-century fantasy Gulliver's Travels starring Jack Black, while Vernon just completed a deal with Sony to make a film based on the classic Sid and Marty Krofft series “H.R. Pufnstuf.”

“Certainly when you're on set shooting, it's a different process, but pre and post-production are becoming very similar," Letterman says of his early experiences making his first live-action film. "We're using many of the same tools. I'm actually finding that pre-visualization is way better in animation. I’m missing a lot of the tools we had on Monsters vs. Aliens."

Vernon agrees that the borders between the two modes of filmmaking are shrinking all the time. "In the future, I don't know what the difference between live action and animation is going to be. I was at Robert Zemeckis' place the other day and saw what he was doing up there. They have these tiny cameras now that are connected to the actors' heads and look back at their face, so you're capturing muscle tweaks and lip quivers and all sorts of crazy stuff. That's the foundation for the characters' facial movements and then the animators go back in and sweeten that. The imagination can take you anywhere these days—it's a technology that will keep getting better and better."