Some movies expand in your brain after you watch them. When I exited the theater after Jordan Peele's 2017 breakout hit Get Out, I was happy with what I'd seen, and I felt like I knew what I'd seen — an ingenious melding of horror-film tropes, comedy and scathing commentary on racism in America.

Peele's follow-up, Us, is weirder, more wandering and in some ways more ambitious. When it comes to messaging, it's certainly less compact and effective than Get Out, more like one of those genre-bending auteur passion projects of the '60s and '70s. When it comes to delivering visceral scares, horror fans may find it wanting. Yet it's the kind of movie that could just haunt your dreams.

Us's subject is one of the classic examples of what Sigmund Freud and others called the "uncanny": doubles or doppelgängers. The film opens with a prologue in which a little girl named Adelaide (Madison Curry) strays from her parents on the Santa Cruz boardwalk and has a terrifying encounter with what may or may not be her own reflection.

Decades later, Adelaide (Lupita Nyong'o) has a family of her own: a likably goofy husband (Winston Duke), a strong-minded teen daughter (Shahadi Wright Joseph) and an oddball son (Evan Alex) who likes to wear masks. After the family visits that same boardwalk, over Adelaide's objections, they receive a surprise nighttime visit from four dead ringers for them.

The doubles move bizarrely, like actors doing movement exercises — sometimes robotic, sometimes feral. Only Adelaide's double is verbal, and she confirms they're not there for a potluck. They come bearing a baseball bat and shears.

For a long stretch, Us plays like a bloody home-invasion flick, with the family fighting off enemies who sometimes seem as mannered and motiveless as the masked killers in The Strangers. Some viewers may find them too mannered to be scary. Certainly, the doubles walk that thin line between the absurd and the disturbing that Peele, as a sketch comedian, knows well; in their distinctly off imitations of normality, they make normality itself strange. That alienating effect, too, is part of the uncanny.

But, just when you may think you have the movie's number, things abruptly get disturbing in a whole new way. The scenes that bookend Us's more conventional scares take us to dark, hidden places that cinematographer Mike Gioulakis (It Follows) fills with oily, sinister bursts of color. They're the kind of dream spaces that Freud would claim represent the unconscious. And what we find there could be ourselves.

Get Out drove home its point by depicting racism in literal terms as well as by using familiar horror tropes (the mad scientist) as metaphors. Us is more elusive, forcing viewers to ask who they should be rooting for. Surely the protagonists who are fighting for their lives, right? Well...

Nyong'o especially helps foster that ambiguity with her creepy, layered performance as Adelaide's double. Asked who the doppelgängers are, she has a one-word answer: "Americans." It's a laugh line that keeps resonating until it becomes tragic and then, just maybe, as scathing an indictment as anything in Get Out.

Not since the original Night of the Living Dead has a movie been quite so earnest and insistent in its reminders that the "others" we fear could, under other circumstances, be us. Us is lopsided and heartfelt and possibly overlong, but anyone who's a little worried about the future of "Americans" right now will find its final image impossible to dispel.