In “Black Box,” it’s bad enough for Nolan (Mamoudou Athie) that, half a year after losing his wife in an automobile accident that also put him into a temporary coma, he’s still suffering from amnesia. But what’s worse are his dreams, which are increasingly becoming nightmares.

And the fact that one morning he wakes up and sees a hole in a wall that he’s told he punched.

Except he’s not a violent person, or even a temperamental one. “I couldn’t even get you to watch boxing, let alone do it,” Nolan’s best friend Gary (Tosin Morohunfola) tells him when speaking of these disturbing circumstances. Gary, who’s a physician, recommends that Nolan visit Lillian, the department head at a medical college, who’s a leader in experimental treatments for neurological dysfunction.

Lillian is played with soothing maternal notes — at least at first — by Phylicia Rashad, who honed that performance mode on “The Cosby Show” many years back. With the movie’s title technology and more, she creates a mental “safe room” for Nolan in which he can uncover memories.

Which he does. Except they may not be his. And they’re not pleasant. They’re also interrupted by a figure walking backward on his feet and hands coming to beat up on Nolan.

Black Box
Not rated. Running time: 1 hour 40 minutes. Watch on Amazon Prime Video.