The Baby is everything you would wish for in an exploitation flick and more: uber-weird, disturbing, and one-of-a-kind. Not to mention that it’s got some dynamite acting and a surprising amount of heart.

Social worker Ann Gentry (Comer) has just taken the case of the Wadsworth family and now oversees the care of the baby son. Trouble is Baby, as he’s called, is a fully-grown man (Manzy) whose mental growth ceased advancing beyond the infant stage. He still crawls about the floor, wears diapers, and can only communicate in cries and whimpers.

Heading this unit is Mrs. Wadsworth (a terrific Ruth Roman), a matriarch who has icy grit and loving maternal instincts in equal measure. Daughters Germaine and Alba (Hill, Zenor) take charge of rearing the man-child—literally in Germaine’s case, as she enjoys crawling into Baby’s crib sans nightie.

Ann eventually grows attached to Baby to the jealousy of his mother and sisters. When Ann plans to remove Baby from his mother’s care in order to see to his development, Mama and the girls decide to see that the nosy welfare lady meets with an untimely accident…

This groovy drive-in number is richly steeped in its time period, complete with a disco dance party that has Michael Pataki showing up as a grass-smoking creeper. Its oddity could have only come from the 70s; where else would you see a young babysitter breast-feeding an adult man?

But The Baby manages to be more than just shock fodder. The scenes of Ann playing with Baby and looking through photos of her late husband are genuinely touching, greatly due to Comer’s strong performance as the nurturing and persevering Ann.

There to fight her every step of the way is Ruth Roman (Day of the Animals, The Killing Kind) as Mama Wadsworth. She’s a dynamo, looking like an even brassier version of Liz Taylor’s Martha from Who’s Afraid of Virginia Woolf? With gravelly voice and intense stare, she’s one of the more memorable horror villainesses of the era.

Hill and Zenor are just as good as her kooky daughters, as is Manley as Ann’s mother-in-law. The film becomes a fantastic ensemble piece in the hands of its actresses.

Top that with a climax that packs not one but two nice twists (though the second calls into question some of the character’s motivations) that has Ann taking some much-deserved vengeance on her tormentors and a lingering final shot and you have a truly fascinating, strange little bird.

As looney tunes as The Baby can be, you have to admit that they just don’t—and couldn’t—make ‘em like this anymore.