Hunchbacks are born into a caste of lab assistants under mad scientists. All named Igor, their duties include throwing the switch to power-up their masters’ experiments, and to affect speech impediments borrowed from their counterparts in old movies. Smartly rendered with cynical detail that’s sure to elude kids—yeah, so what?—this PG animated tale depicts one Igor (voiced by John Cusack) who dares to dream of a caste upgrade. All he has to do is invent his own weapon of mass destruction to terrorize Earth, and win the Evil Science Fair just one week away. His sidekicks are a dim brain who mislabeled his jar “Brian” (Sean Hayes) and Scamper (Steve Buscemi), a woebegone wabbit with an existential death wish thwarted by Igor’s software that makes him immortal. Igor concocts a towering uber-warrior (Molly Shannon). But there’s a glitch in uploading her motivation as a mass killer. Instead, segments of James Lipton’s “Actors Studio” cable show turn her into an aspiring star of “Annie.” She blares the show tune “Tomorrow” like a death ray. Director Tony Leondis (“Lilo & Stitch 2”) and writer Chris McKenna populate their morose Kingdom of Malaria with characters named Dr. Schadenfreude. Tasty, nasty touches abound: Igor’s homeland funds itself by blackmailing the rest of the world with the annual winner of the Evil Science Fair. Kids can get that part. With voicing by John Cleese, Jennifer Coolidge, Arsenio Hall, Sean Hayes, Eddie Izzard, Jay Leno, Molly Shannon and Christian Slater. 86m. (Bill Stamets)