Saw director James Wan and writer Leigh Whannell ditch the blood spilling and go for blood-chilling with *Insidious*, the most thoroughly terrifying film since its influential ancestor Paranormal Activity. After an accident in his new home, little Dalton (Ty Simpkins) goes into a mysterious coma, a development that coincides with much supernatural weirdness. His parents (Patrick Wilson and Rose Byrne) consult an expert in otherworldly matters (Lin Shaye), who tells them that malevolent fiends are trying to steal Dalton’s soul while he sleeps. With Paranormal Activity director Oren Peli on hand as producer, Wan delivers an object lesson on the importance of sound in horror movies, wringing chest-constricting tension from ticking clocks, creaking doors and extended stretches of near-total silence. By the time the explanations about “astral projection” are trotted out, your nerves are so frayed you don’t question the hokum.