It’s been a decade since “Child’s Play,” when we first met Chucky — a murderous doll stitched up with the soul of a dead killer and a face like Michael Keaton’s. But in doll years, he’s a decrepit old man, better left in the 1980s horror-franchise grave. This fourth upchucking of cartoonish gore, directed by Ronny Yu from a script by Don Mancini, leans heavily on self-referential gags: Among the hardy-har names dropped by the Chuckster (voiced, as ever, by Brad Dourif) and his dolly girlfriend, Tiffany (Jennifer Tilly, pushing her squeaky sex-bomb act beyond camp limits), as they terrorize full-lipped teens are Jerry Springer, Barbie, Ted Bundy, Jeffrey Dahmer, and — ooh, scariest of all — Martha Stewart. John Ritter makes an appearance as a mean police chief; Kathy Najimy has an even briefer cameo as a motel maid. At one point, when Tiffany’s still a fleshy villainess rather than a plastic one, she reads Voodoo for Dummies. This is teen horror for dummies.