*** stars
Opens Friday

For several years now, I’ve held the considered opinion that Jessica Chastain is the single most beautiful creature on the planet. Now I know the truth: Jessica Chastain dressed as a goth rocker is the most beautiful creature on the planet.

Chastain’s lovely performance regularly elevates Mama, the very effective new paranormal thriller from producer Guillermo del Toro and first-time director Andrés Muschietti. Fans of del Toro’s previous horror movies (The Devil’s Backbone, Pan’s Labyrinth) will recognize his sensibilities all over this thing.

The film opens with a disturbing scene. A distraught father, who has apparently just killed his wife, speeds off in a car with his two little girls. The car crashes and dad leads the kids to a creepy old cabin in the woods. Some very scary things happen, dad doesn’t make it, then we flash forward five years.

The girls, now age nine and six, are finally discovered — still in the cabin and living like feral cats. Actually, the way they skitter around on all fours is more insect-like and this is the first of the many, many disquieting images director Muschietti has in store.

The girls are eventually adopted by their uncle Lucas (Nikolaj Coster-Waldau, Jaime Lannister to you Game of Thrones fans). Lucas’ girlfriend Annabel (Chastain) isn’t crazy about raising two untamed forest kids. But she becomes more agreeable when the local research institute offers a beautiful rent-free home, in exchange for permission to study the kids.

It soon becomes apparent that the little girls have brought a companion with them, a maternal yet decidedly terrifying presence from the other side of the grave. This is Mama. She’s been looking after the kids for years and is none too happy with the new custody situation.

Weird things start to happen around the house. Windows open. Doors slam. Annabel’s bass amp starts channeling otherworldy voices. Muschietti delivers one brilliant, unbroken shot in which the girls lose history’s scariest tug-of-war match. Also keep an eye on those paintings on the walls.

There are five or six code-red scares in this movie, shocks so jolting that at one point I literally did the thing where the popcorn goes flying. Muschietti makes some interesting moves here by switching up the standard horror movie rhythms. He builds to the scary shot we’re expecting and delivers it with a flourish.Then it gets scarier. And scarier. And scarier still.

Chastain provides the emotional base the film needs to power its creepshow set pieces. Annabel truly does not have a maternal bone in her body. But she’s strong and decent and does not like bullies, spectral or otherwise. Annabel doesn’t act like a horror movie heroine. Just when we think she’s going to zig, she zags.

Interestingly, the men in the movie are shuttled offscreen for much of the film’s running time. Other than looking impossibly handsome, Coster-Waldau doesn’t make much of a contribution. Daniel Kash puts in a nice performance as the psychiatrist who uncovers the terrible nature of the haunting.

Mama starts to unravel a bit at the end, with characters getting jerked around so the right people are at the wrong place at the wrong time. And the ending didn’t quite work for me. After a delightfully creepy 90 minutes of glimpsing Mama in flashes and blurs, Muschietti gets right in your face with the big, bombastic climax. The effects are dazzling, but the tone is wrong.

That’s a minor complaint, because ghost stories this good are really hard to pull off, and ending them properly is almost impossible. Kubrick is the only one who nailed it, when he put Jack Nicholson in the old photo in The Shining.

Mama is a good scary movie with flashes of greatness. Don’t read up too much on it if you want to preserve the surprises. And hold onto your popcorn.