The latest entry to the overcrowded vampire-flick field is “Cirque du Freak: The Vampire’s Assistant,” which arrives with quixotic dreams of a franchise of its own. The source material this time is a series of young adult books known as “Cirque du Freak” by Darren O’Shaughnessy — who writes under his protagonist’s name, Darren Shan.

We meet the world of “Cirque du Freak” through Darren (Chris Massoglia), a popular, straight-A high-schooler whom his rebellious best friend, Steve (Josh Hutcherson), calls “Mr. Perfect.” Though Darren is wide-eyed and naive, he harbors a love of spiders. Steve idolizes vampires.

Both get a front-row seat to their dark secrets when a traveling freak show comes to town. They’re lured in by a mysterious flyer tossed from a spooky black car (license plate: “DES-TINY”). At the show — with the help of some digital effects — is a bearded lady (Salma Hayek), the very tall Mr. Tall (Ken Watanabe), a superthin man (Orlando Jones), a snake boy (Patrick Fugit) and others. The main attraction, though, is Crepsley (John C. Reilly), whom Steve recognizes as a vampire.

Darren and Steve quickly and carelessly involve themselves with the group. Darren is taken in by Crepsley and lives among the freaks of the touring circus. Steve casts his lot not with Crepsley, but Muraugh (Ray Stevenson), a “vampaneze.” It turns out that there’s a centuries-long feud between vampires (who merely sedate their prey and take a taste of blood) and vampaneze (who still take the vulgar, old-fashioned approach to killing people).

Reilly (a fine actor out of place here) takes being a vampire seriously, but his best bits are his amusing scoffing at conventional vampire traits. Such jokes are the highlights of the film and suggest what it could have been: an out-and-out comedy. Director Paul Weitz should have known that, too, having helmed the solid 2004 comedy “In Good Company,” 2002’s “About a Boy” and 1999’s “American Pie.” Instead, “Cirque du Freak” might be the single most overstuffed movie of the year. You have a high school film crossed with a vampire film crossed with a mutant film crossed with Willem Dafoe cameos. The supernatural never establishes itself as anything but ridiculous.