The quality of the Happy Madison pictures starring Adam Sandler has been low and getting lower, but that of the ones in which he doesn’t have the lead has been even worse. It makes you wonder whether all the scripts are originally intended for him, but he shunts off the ones he thinks beneath him to chums like Rob Schneider. That would be a plausible reason for perpetual second-stringer Nick Swardson taking the lead in this comic monstrosity. “Bucky Larson: Born To Be A Star” is beneath us all. It plays like an unfunny idea for a raunchy five-minute sketch that’s been cruelly extended to an insufferable ninety-six minutes.

Swardson, boasting prosthetic buck teeth that rival Bugs Bunny’s and a Prince Valiant page-boy haircut that might make Robert Wagner envious, is the titular goofball, a naïve dimwit from Iowa (all the Iowans are depicted as idiots) who finds out that his blockhead parents (Edward Herrmann and Miriam Flynn) were once porn movie stars. (The discovery comes during a stag movie night with his almost-as-stupid friends, during which they instruct Bucky in how to masturbate.) Suddenly the lad is overcome with the desire to go to Hollywood to become a porno star himself.

There he makes the acquaintance of down-on-his-luck director Miles Deep (Don Johnson), who gives him an audition that falls apart when the boob exhibits a penis that in a later scene will be characterized as straw-sized and ejaculates wildly at the slightest provocation. But when Miles has the brilliant idea that pictures starring him will appeal to all the guys with less deficient prowess (and their significant others), he turns Bucky into the industry’s star of the year, much to the anger of heretofore reigning champ Dick Shadow (Stephen Dorff).

Interspersed with the hero’s climb to fame is his unlikely romance with Kathy (Christina Ricci), a sweet waitress in a dismal diner who gets him a place to stay with a psychotic neighbor (Kevin Nealon) but otherwise supports him unstintingly. One of the so-called jokes is that Bucky helps her overcome a fear of carrying large trays of hot food so she can get a job at a really fine restaurant.

There’s nothing remotely humorous in any of this, but it’s made as terrible as possible by Tom Brady’s hapless direction, and by Swardson’s positively creepy performance as Bucky, who’s meant to be a charming naif but comes across as a mentally-shortchanged weirdo. The idea, one supposes, was to recreate what Jerry Lewis did when he put on false teeth and played the fool, but even Lewis was much more likable than Swardson. Matters aren’t helped by the manic overplaying of Johnson and Nealon, both apparently trying to wring some laughs from their miserable material, and you have to feel really sorry for the indignity that Flynn and Herrmann suffer. Dorff charges into his role with gusto, but never makes Shadow anything less than repulsive. Ricci, by contrast, is pleasant and restrained. Why this beautiful, talented young actress allows herself to be trapped in such rubbish remains a total mystery.

The only other person who comes out of this sleazy mess without humiliating himself is—believe it or not—Pauly Shore, who acts as the host of the adult film “academy awards.” It pains me to say it, but sitting through “Bucky Larson” might make you long for “Jury Duty” or “Bio-Dome.” Well, not really. But it’s just as awful as they were.