Can someone explain to me why Gru, a man with no neck, wears a scarf? Is it a fashion statement? Do supervillains even care about fashion? I don’t get it.

There’s a lot I don’t get about the Despicable Me franchise — primarily why it is so phenomenally popular. To date, the two films about Gru (Steve Carell), reformed baddie and unlikely daddy, and the spinoff about his little yellow sidekicks, the Minions, have grossed $2.6 billion worldwide. (Despicable Me 2 is supposedly the most profitable movie in the history of Universal Pictures.) All this despite the fact that none of these movies are particularly fun or inventive or memorable; at their best, they’re mindless children’s entertainment. And they’re rarely at their best in Despicable Me 3.

This latest collection of slapstick, wacky voices, and fart jokes — the first of which happens before the title appears onscreen — follows Gru and his new wife Lucy (Kristen Wiig) after they get fired from their jobs at the Anti-Villain League, whose leader (Steve Coogan) is inexplicably replaced after just one scene by a new boss (Jenny Slate) in a storyline that is then dropped from the film completely and never mentioned again. The Minions want to return to a life of crime, so they walk out on Gru right as he learns he has a twin brother he’s never met named Dru (also voiced by Steve Carell). Jobless and broke, Gru and his family travel to Dru’s home in Freedonia, where Gru’s daughter Agnes (Nev Scharrel) searches for a unicorn while Dru tries to convince his brother to help him get into the family business.

It barely sounds like a movie, right? Despicable Me 3 plays less like a feature than a collection of overlapping shorts: Gru & Dru getting to know each other, the Minions getting thrown into and then breaking out of jail, the nonsense with the unicorn, plus Gru and Lucy’s pursuit of another supervillain named Balthazar Bratt (Trey Parker). Even by the standards of Despicable Me, Bratt is strange: A former child star of a TV show about a kiddie supervillain, he went insane after his show was canceled and adopted his fictional character’s evil persona in real life. Bratt also has two different cliched ’80s haircuts simultaneously, a flat top and a mullet, and he likes to dance to ’80s music while he commits his crimes. He and Gru fight (and often dance fight) over a diamond that Bratt needs to power a giant robot version of the action figure from his old TV show that he plans to use to destroy Los Angeles with bubble gum bombs and lasers.

Okay, sure.

It would make sense if Bratt’s general weirdness was an excuse to let Parker, who’s created some of the most distinctive animated characters in history, flex his vocal skills. Instead, he’s just another guy with a goofy costume and weapons. Literally anyone could have provided Bratt’s voice; the hair and silly dancing do all the work. Carell is still charming as the mysteriously accented Gru, and his totally different mystery accent as Dru is good for a couple more laughs. But the sibling rivalry between the two never develops into something substantial.

Nothing in the movie does, really. Despicable Me 3 isn’t terrible, per se. It isn’t anything. The animation, directed by Pierre Coffin and Kyle Balda, is bright and energetic, and there’s a certain amount of invention in the villains’ various gadgets and vehicles. (I like Gru and Dru’s flying car, which can also float and climb walls.) But the script, characters, and gags are forgettable in just about every way.

In the big climax, Bratt’s giant toy robot rampages through Hollywood. In a smarter movie, that would be a clever meta-commentary on the way toyetic franchises are systematically destroying the American movie industry. Not in a series as heavily merchandised as Despicable Me. They even sell Gru costumes complete with a shirt, pants, mask, and scarf.

Additional Thoughts:

-The first Despicable Me wasn’t even the best animated movie about a former supervillain released in 2010. That was Megamind, which had a much more impressive voice cast including Will Ferrell, Tina Fey, and Brad Pitt. But it didn’t have those damn Minions. Kids love the Minions.

-Yes, Dru lives in the fictional country from the Marx Brothers’ immortal classic Duck Soup, an homage that is neither appropriate nor earned. To paraphrase Groucho, I’ve had a perfectly wonderful evening, but watching Despicable Me 3 wasn’t it.