Filmmakers dont get much busier than Guillermo del Toro. The native Mexican who now calls L.A. his home gained notice with his first feature Cronos an odd little horror film about eternal life two decades ago. Some ups and downs followed, but he found major success with the much odder (and funnier) Hellboy and its sequel, and cemented his reputation as a true artist with the haunting Pans Labyrinth.

In between those films, hes also been an in-demand producer (Puss in Boots, Rise of the Guardians).

But the longtime devoted fan of old Japanese monster movies has had the massive sci-fi epic Pacific Rim kicking around in his head for years. He recently spoke about his resulting tale of the battles between giant Jaegers (human-controlled robots) and huge Kaiju (Godzilla-like sea creatures).

Did you design all of the Kaiju?

When we started to flesh out the script (screenwriter) Travis Beacham came to my house, and I locked him in my man cave. In my garage I have a design room that accommodates eight to 10 artists. I was in another room, writing part of what Travis and I were co-writing. Every day, five or six times a day, I would give Travis what Id written, and he gave me what hed written. I would go check on the artists, and we designed every Kaiju, and every Jaeger, in my garage.

The films visual effects are amazing. What sorts of technology did you use?

Ive been doing special effects since I was a kid. I did them professionally for over a decade. Im familiar with and comfortable with every tool. I can use the latest or I can use the oldest technique. The misconception is that there are good ones and bad ones. I think digital effects are as great and valid as any of the others. But the tragedy is to use them as a shortcut creatively.

The solution does not have to be a visual effect. We used miniatures; we used incredibly elaborate physical effects. For instance, a street in the film was rigged with hydraulics. The whole street the pavement, the walls, the lampposts, the cars, the sidewalk everything. So every time the Kaiju took a step, the whole street jumped. The easiest thing is to just shake the camera and put in a digital effect. You just have to not be lazy. We built a hundred physical sets in this movie. Normally in a movie like this, they dont build; they just use digital. But I think that doesnt inform your actors. Your actors end up saying, What am I looking at? What am I supposed to feel about this place?

Youve often spoken about being fascinated by Japanese monster movies when you were growing up. Do you have a favorite?

I know them all. I live in a house that has one section entirely dedicated to Kaiju. But my favorite movies are two that are not the most famous ones: Frankenstein Conquers the World and The War of the Gargantuas. They have a lot of pathos, and they made me weep. When the creature in Frankenstein is in love with the girl, Im going, Awwwww, I wish she paid attention to him. But my favorite Kaiju is Pigman in Ultraman. Hes a very moving, sort of sad little Kaiju.

As a child or even now as an adult, which monster have you feared the most?

I fear politicians. I think the worst monsters in the world have nice suits. I dont fear monsters. Well, the only monsters I kind of fear, because I think of myself as a mortal, are zombies. I dream of zombies chasing me. Also sharks. I find myself edible (laughs).

Pacific Rim opens on July 12.