As funny as a mass shooting at the North Pole, and relying on just such a finale to sell it, “Fatman” is one of the epic miscalculations of any cinematic holiday season.

And I say this as somebody who adored “Bad Santa,” who finds Mel Gibson‘s B-movie Purgatory a fascinating turn in his career (gritty, lowdown action pics) and laughs at pretty much anything Walton Goggins says or does.

Throw all that out with “Fatman.” It’s a Gibson shoot-out sh-tshow pitched as a dark comedy. Eighty-two minutes without a single solitary dying-of-loneliness laugh, then the first and only chuckle arrives and the real mayhem begins.

The writer-director siblings of “Small Town Crime” lured Gibson, Goggins and the wonderful Marianne Jean-Baptiste (of “Secrets & Lies” and the most recent “Robocop” reboot) into a movie with little point and even less entertainment value, a lump of coal just in time for the holidays.

In a cynical time not unlike our own, Chris Cringle (Gibson) has “lost my influence.” His small town (North Peak, Alaska) sweatshop of elves isn’t meeting its numbers any more. Because, frankly, we’ve raised a generation of brats.

“This is Christmas, we’re not handing out PARTICIPATION trophies,” he grouses to a dissatisfied client. “All I have is a loathing for a world that’s forgotten,” he whines to his wife (Jean-Baptiste).”

So it’s no wonder that “the whole operation’s goin’ tits up.” It’s no wonder that he’s hitting his local watering hole for his “usual” (“a Johnny Carson,” whisky and Alka-Seltzer, a “Mad Man” favorite).

Working the phones, begging Elon for contracts, doesn’t cover their nut. Maybe the military needs some cheap labor.

But one of those brats has the means of getting even when he doesn’t get what he wants under the tree. Rich Billy (Chance Hurstfield) has “our friend” on retainer, an enforcer-hitman (Goggins) who ensures that the kid wins every science fair, filling the void the child’s always-absent father leaves.

Billy’s cruelty hasn’t gone unnoticed. Because “he sees you when you’re sleeping,” etc. But seriously, a lump of COAL?

“I’d like you to KILL Santa Claus.”

California’s Nelms brothers bring all that they don’t know about dark comedy to Canada for this production, filling the film’s first hour with Santa’s struggle for fulfillment and making payroll and the hitman’s hunt for “Fat Ass,” as he refers to the fellow in the red suit we never see the Fatman wear.

We do see a reindeer. “That’s Donner. Sometimes he gets a mite nippy.” And apparently Santa’s used to getting shot at, and shot — flying low over GunNut Nation and all. Gibson loves self-surgery scenes.

Meanwhile, our hunter is picking his weapons, Schwarzenegger style, and attacking US Postal workers, Louis DeJoy fashion, in his hunt for an address.

Hilarious.

Even though it’s been a while, we know Gibson can do comedy. Even he can’t turn “I’m just a silly fat man in a red suit” funny.

Goggins has even less to work with. Even his way with an F-bomb falls utterly flat here.

Humor is the most subjective entertainment form to review, and the best anybody can manage is to try and approach a movie like “Fatman” on its own terms. I was primed for this to work.

In this case, that doesn’t help. Nothing does.

Cast: Mel Gibson, Marianne Jean-Baptiste, Chance Hurstfield and Walton Goggins

Credits: Written and directed by Ian Nelms, Eshom Nelms. A Saban Films release.

Running time: 1:40