If the great god of movies, whatever slippery Mount Olympus of money he resides on, decrees that summer is the time for larger-than-life 3D blockbusters, Guillermo del Toro may as well make one. His Pacific Rim is summer entertainment with a pulse. The effects are so overscaled and lavish as to be occasionally mindless . But then, the deep-sea monsters that populate the movie-- scaly, nubbly, pissed-off behemoths called by their Japanese name, kaiju-- are also motivated by something primal, a drive that can't be readily explained. Their summer job is a simple, glamorous one: qualifications include being able to breathe electric blue fire, or to open several of their false mouths before revealing the really treacherous maw. What reason for existing do they need, other than to lure us to the theater? For del Toro, the creature is the feature. Giant robots matter to him too, but less so. And unlike listless robotsploitation exercises like Iron Man 3, Pacific Rim is big and dumb in a smart way. The movie's brief voiceover prologue explains: In 2015, one disgruntled kaiju after another rose from the ocean to come ashore, smashing cities like San Francisco, Manila, and Cabo, until it was discovered that the big bruisers could be defeated by giant manned robots known as Jaegers. Phew! Everything you think is going to happen does. One character chokes at the moment of truth; noble warriors sacrifice for the cause. But del Toro shapes the movie so it's not just one booming attack after another: There's breathing space amid the action, and in a gorgeously choreographed sequence, old-fashioned hand-to-hand human-to-human combat becomes its own special effect.