Perhaps you may recall, in your younger years, asking a random adult to buy you booze. Desperate times and all, but it’s surprising just how many strangers will end up accepting your proposition. Ma, the latest from director Tate Taylor (The Help) uses that awkward exchange as an inspired set-up for a stalker horror flick. Unfortunately, the end result — while amusingly idiotic — is neither depraved nor inventive enough to leave an impression.

When Maggie (Diana Silvers) and her friends find a willing adult in the form of Sue Ann (Octavia Spencer), they get more than just a booze hookup; she offers up her basement so they can throw all the sloppy high-school parties their hearts desire. That motherly generosity earns her the nickname “Ma” from the youngsters. There’s only a few house rules: No drunk driving, no swearing and don’t go upstairs. No prizes for guessing something sinister is afoot. All it takes is a glance at the movie’s poster to surmise that Ma is a fucking psycho.

While Ma is always watchable and even modestly entertaining in certain stretches, Spencer is the movie’s real selling point. The actress is predictably excellent in the title role and clearly savors each time she gives a character a friendly smile, only for it to give way to a menacing glare once they walk away. That happens about six times. Her casting also serves as a clever inversion of the African-American “mammy” archetype by crafting a mother figure that’s malicious instead of doting. The movie doesn’t really do anything with it, but it’s a nice touch nonetheless.

The other characters don’t fare as well. Kudos to screenwriter Scotty Landes for not leaning too hard into Maggie’s father recently leaving her. Though she doesn’t have much of a personality, the character doesn’t succumb to the virginal final girl or moody outsider tropes that befall so many other teen characters. The rest of her friend circle is a parade of walking stereotypes, however, from the promiscuous party girl to the character whose every line of dialogue is a reference to him being black.

We’ve seen countless crazed stalker movies in the past (even earlier this year with Greta), so for one of these to stand out, it either has to find a way to subvert the genre’s formula or go to some truly perverse places. There is a surprisingly gruesome sequence late in the runtime that threatens to take Ma into torture-porn territory and do some downright weird shit, but that ends up being the last of the movie’s few surprises. Truth be told, nearly every aspect of the plot is predictable to a T, and never more so when we’re given brief flashbacks into Ma’s high school years that play like a Lifetime ripoff of Carrie.

About that Lifetime aesthetic: There’s a cheapness to Ma’s look that’s ill-fitting even for a Blumhouse budget. This does not have the sleekness or ingenuity of that studio’s Get Out or Halloween reboot. It wouldn’t seem out of place as a made-for-cable movie on the Oxygen network. Part of this issue has to lie at director Taylor’s feet. There is absolutely nothing distinct about the filmmaking — lacking even a whiff of genuine vision, which ultimately makes the bulk of this feel generic, especially when Spencer’s not on screen.

Ma boasts one of the year’s most effective trailers, promising whiplash plotting and escalating insanity anchored by a bellicose Spencer. Instead, it’s a pretty rote thriller with a neat premise on which it never fully capitalizes. The best kind of trash commits to its lack of taste without any shame while the worst kind feels the need to let its audience know it’s in on the joke. Ma doesn’t have the guile to do either.