When Octavia Spencer and “The Help” director Tate Taylor teamed to bring mad-as-hell ’60s Southern maid Minny Jackson to the screen, the vivid result earned Spencer an Oscar. The two are back at it with “Ma,” a psychological thriller about a lonely woman whose chance connection with some party-minded teens takes a drastic turn. And this time, the over-the-top craziness that Spencer slyly serves up fills more than just a pie plate.
Diana Silvers (“Booksmart”) gets her own nifty showcase as new-girl-in-school Maggie, whose general level-headedness doesn’t keep her from accepting an invite to go backroads cruisin’ and underage boozin’ with brassy Haley (McKaley Miller) and her peeps. As the gang nervously fumbles to find a package store patron to set them up, they come across Sue Ann (Spencer), an innocuously dowdy passerby — but, sheesh, chatty! — in pink veterinary scrubs and a time-capsule Dorothy Hamill cut. She fills their liquor order with a nostalgic wink and a maternal note of caution, easygoing enough that the kids are only passingly suspicious when she subsequently offers them her basement as a DUI-preventing hangout.
Then the surprise drop-ins start at school. And the serial texting. And the odd thumps from Sue Ann’s off-limits rooms upstairs. Taylor and the cast build suspense not just with hints of what Spencer’s giddily unbalanced oddball is up to, but by keeping us actively guessing what’s driving her — if rational motivation is even in play here. Interactions with Maggie’s mom (Juliette Lewis, all credible, world-weary stress) and another parent (alternately warm and cool Luke Evans) deepen the intrigue. (Be warned: the late going gets awfully gnarly. It makes us wonder whether “The Help” was actually atypical territory for Taylor, whose last feature was “The Girl on the Train.”)
Meanwhile, it’s no mystery at all what’s motivating Ma’s too-trusting new pals. But the teen set’s to-hell-with-better-judgment vibe also feels reasonably honest. Nice work here from both the young cast and writer Scotty Landes (“Workaholics”), who nimbly captures the kids’ voices. (Love the throwaway “graceful” that Maggie snidely drops as Haley awkwardly clambers through a cellar window.)
Still, as the movie’s succinct title makes clear, Spencer is the draw. You’ll come for the chance to see her following in the bonkers footsteps of Kathy Bates and “Misery” — wonder if “Sue Ann” is an intentional nod to Annie Wilkes? — but you’ll also hang in for the raw depictions of emotional scarring. The lady might be a wackjob, but she’s one with some complexity behind the creeping instability. As showy character roles go, Spencer hits the motherlode.
Directed by Tate Taylor. Written by Scotty Landes. Starring Octavia Spencer, Diana Silvers, Juliette Lewis, McKaley Miller, Luke Evans. At Boston theaters, suburbs. 99 minutes. R (violent/disturbing material, language throughout, sexual content, teen drug and alcohol use).