I’m sick of all the “Napoleon Dynamite” copycats, and I actually liked “Napoleon Dynamite.” I can only imagine how the people who hated it must feel about its imitators. It must be like rubbing salt in the wound.

Those wounds will feel especially salty after “Terri,” a vulgar version of “Napoleon Dynamite” in which the title character is an obese, buffoonish teenager who goes to school in his pajamas and catches mice to leave out in the woods for a local hawk. (I assume that yes, the hawk has sharp talons.) Terri lives with his elderly, bewildered Uncle James (Creed Bratton) and befriends a fellow oddball named Chad (Bridger Zadina), who’s as bizarrely skinny as Terri is fat.

Terri is played by Jacob Wysocki, a very floppy and apparently unself-conscious young man who makes Jonah Hill look like Seth Rogen. I don’t mention his corpulence merely out of cruelty; the film, directed by Azazel Jacobs, is highly interested in it, too. The first time we see Terri, he’s soaking in a bathtub, the camera mercilessly observing all his folds and flaps. His shape figures prominently in everything he does throughout the film.

The kids at school are generally pretty mean to Terri, but he becomes a minor hero when he defends a girl whose boyfriend took inappropriate liberties with her during home economics class. The girl, Heather (Olivia Crocicchia), appreciates Terri’s sense of justice. Meanwhile, the assistant principal, Mr. Fitzgerald (John C. Reilly), starts meeting with Terri on a weekly basis, possibly because he thinks Terri is mentally handicapped.

You probably know that John C. Reilly’s presence in a comedy is a harbinger of good things, and his loony behavior as the unstable Mr. Fitzgerald is this film’s greatest asset. To the extent that there is any “message” to the story, it’s expressed by Mr. Fitzgerald, speaking to Terri: “Life’s a mess, dude. We’re all just doing what we can.”

That’s nice and all, but “Terri” is largely pointless, and while pointlessness isn’t necessarily a bad thing in a comedy, it must be accompanied by, well, comedy. Patrick Dewitt’s screenplay simply isn’t very funny. It’s inconsistent at best — an absurdly amusing scene here, an outrageous bit of mayhem there — and doesn’t add up to anything thematically. That makes it a particularly pointless brand of pointlessness.

Of course, anything related to the funny bone is bound to be subjective; the humor in “Terri” might be up your alley more than it was up mine. I’m not even opposed to the mockery of fat people, if that’s what you want to do, but Jacobs doesn’t really commit to it. The meanness toward Terri is more casual than calculated, without the payoff that comedy demands. The sensation is uncomfortable, and not the enjoyable kind.

C+ (1 hr., 41 min.; R, a few F-bombs, some vulgarity, some sexual images and conversations.)