I’ve always had a soft spot for Beavis and Butt-Head.

Or maybe that was just the Dulcolax doing its job.

But here they are, 29 years after their MTV debut, moronically sniggering and slap fighting their way through their second feature film.

“Beavis and Butt-Head Do the Universe” rips off the plot to “Space Camp,” and slaps a dab of “multiverse” on it to let us and all those Marvel suits know that particular sci-fi plot twist is officially “played.”

Yes, our two “heroes” have gotten up from the couch, stopped calling David Lee Roth “fat boy” and Ozzy “an old fart” to set out on an epic journey through space and time, “a quest to score.”

It’s about as funny as your average episode — OK episode and a half — of their long-running, on and off series. Except it’s padded with 45 minutes of “We’ve lost our fastball.”

“Ball… hehehehehe.”

They’re back and Butt-Head wants us to know where they’ve been since 1998 (the series came back in 2011, briefly). And therein lies the tale. It begins with a ruined Highland High science fair which earns them a misguided stint at Space Camp as “two at-risk youths.” Their days at Johnson Space Flight Center — “Hehehehehehehe…’Johnson’ — let them show that they’re really good — obsessed — with uh, “docking procedures.”

“Huhuhuhuhu…”

So the next Endeavor shuttle mission brings them along. Mayhem ensues, people die and these two — sure this is all just foreplay from the mission commander (voiced by Andrea Savage) who “wants to score” — wind up drifting into a black hole.

No, neither Beavis not Butt-Head (both guys are still voiced by creator Mike Judge) can’t let “hole” can let that pass without sniggering notice. Or misunderstood panic.

“I don’t want to die in a Butthole! I have dreams about it all the time!”

They find themselves in 2022, with cell phones, the sexy-sounding Siri app, Kia Souls and college gender studies classes, where they do a broad wingnut-friendly “teachable moment” riff on “white privilege.”

Fair enough. Just not as funny as them, with Beavis shifting into his Cornholio guise, winding up in prison.

Beavis: “That youth pastor always said we’d end up in here some day!”

Butt-Head: “The system works, Beavis.”

The “two idiots” are chased by Men in Black and the former shuttle commander, now a sinister Texas governor with a dirty secret — she “killed” them — she is determined to keep.

And there are smart “alternate universe” versions of the characters that pop up with an urgent plea, which falls on dim and deaf ears. Because stupid Beavis and Butt-Head are as stupid as ever.

Despite making an effort to offend, here and there, the characters have lost some of their edge and Judge can’t help but suggest “old fart” in still attempting to manage those grating, giggling pubescent voices.

Will this movie be enough to create a new generation of fans? No. That’s why it ended up on Paramount+, where we old farts can get nostalgic and remember funnier moments from them, their earlier movie and their heydays in MTV’s golden age, with or without the Dulcolax.

Rating: TV-14, profanity, toilet humor, innuendo

Cast: The voices of Mike Judge, Andrea Savage, Tig Notaro, Gary Cole and Chi McBride

Credits: Directed by John Rice and Albert Calleros, scripted by Mike Judge and Lewis Morton, based on characters created by Mike Judge. A Paramount + release.

Running time: 1:26