“Companion” is a horrific and caustically cautionary sci-fi thriller about how the digitized alternatives to dating might go wrong. Very wrong.

Signing on an impressive cast, writer-director Drew Hancock takes a big, roundhouse swing at “coupling” in a distracted, instant gratification craving, uncompromising and not-entirely-adult era, and at sending up a rom-com convention or two. But the best he manages is a slow roller to shortstop with this icy, rarely amusing and gory dark comedy.

“Yellowjackets” alumna Sophie Thatcher plays Iris, whom Josh (Jack Quaid) “meets cute” in a supermarket. She is the idealized pale, pert and perfect pixie. He’s the good-looking clod who knocks over the stacked display of oranges.

Iris voice-over narrates about their “instant connection” and the feeling she got from him the day she met him, a feeling repeated at the end of their relationship.

The happy, cute couple is off to spend a weekend with friends at a designer mansion on a private lake. Iris is nervous, as Kat (Megan Suri) doesn’t “like” her, she’s sure. The gay couple, cuddly Eli (Harvey Guillén) and hunky Patrick (Lukas Gage) may accept her. Will Kat’s paramour, the married and sketchy Russian owner of all this exclusivity, Serge (Rupert Friend) be as kind?

Iris frets over how she’ll fit in on the (self-driving) car ride up, and in bed after she’s met and mingled, and after she’s “satisfied” Josh.

“Go to sleep, Iris,” he snaps.

It’s only later, the second time he says this, that we’re told she’s his rented “companion,” the latest tech from Empathix Robotics. We flash back to Josh taking delivery, his assurances that he can control how “smart” and how “strong” she is and how that original “meet cute” was one he selected for their shared “memory.”

Just keep that digital tablet or phone app at hand to “control” her and he’s golden. Or so he’s told.

Hancock — he created the short-lived “My Dead Ex” TV show — works in all sorts of jabs at selfish lovers, rich, rapey louts and the threat such synthetically “perfect” sexual ideals might be to sugar babies like Kat.

“My replacement” is how she sees the attractive but vaguely mechanical Iris.

The scripts ‘revelations are generic thriller cant and the plot places and takes them are quite predictable. That goes for the ways things go wrong and the order that this intimate party shrinks, Agatha Christie style, towards “And Then There Were None.”

I appreciate the ambition here, and there’s potential amusement in the generational digs, romantic illusions and grimly transactional “I just want to make you happy, Josh” Hancock sets up for Generation Gamer/Incel/Reddit rants.

But as horror, there’s nothing here that truly shocks. Covering Thatcher’s pixie in blood is the shortest-lived jolt of all. The deaths have no meaning or pathos. They’re simply perfunctory. The rom-com satire never quite works, except in a suspect-every-relationship where one partner seems “Out of His/Her League” sense.

The “reasons” for all that transpires could have been a slap heard all across Gen Z. But the punch is pulled.

And the cast never overcomes the sterility of it all, although Suri and Friend in particular register as characters with agency and flaws that could be their salvation, or undoing.

Nobody embarrasses himself or herself, but their writer-director lets them down. This “Companion” might have been the perfect picture pitch, but our batter never makes clean contact.

Rating: R, graphic violence, suggestions of sex, profanity

Cast: Sophie Thatcher, Jack Quaid, Harvey Guillén, Lukas Gage, Megan Suri and Rupert Friend

Credits: Scripted and directed by Drew Hancock. A New Line release.

Running time: 1:37