A virtual spoiler siren for itself, the new film Incident at Loch Ness is a double-edged whoopee cushion, and writing about it is an act of summary deflation. (Read: Bugger off.) If you buy the setup (abetted by sly news items planted in the entertainment press and Scottish media since the summer of ’03), it’s yet another documentary about aging gonzo-king Werner Herzog, shot by hallowed veteran DP John Bailey, as the still-plucky adventurer prepares to shoot his own documentary about the phenom of Loch Ness monster culture. The publicity-verité tone is superbly maintained, even as screenwriter hack Zak Penn, who’s producing Herzog’s movie, slowly begins to bully the veteran cineaste with a classic, give-the-people-what-they-want Beverly Hills myopia. Our Man Werner has completed movies in the face of war, disaster, physical impossibility, and cataclysmic lucklessness, but can he weather the dumbed-down mealy-mouthery of Hollywood?

Of course, Penn’s directorial credit suggests an alternate program, and sure enough, the film slowly sheds its convincing identity as nonfiction and becomes a cruel parody of making-of docs, studio-movie pandering, and showbiz egomania. To his credit, Penn comes off as a bloated, hairless, piscine monster, the living embodiment of Hollywood crassness, while Herzog, his individualistic integrity employed as an indomitable counterbalance, is the infuriated straight man. (Bailey, the ostensible auteur of the movie, is unseen until the rancorous end of the journey, answering the camera after he’s been fished out of the loch with a wiped-out “Fuck you.”) The rich dynamic comes down to Penn’s whiny, off-camera comment, “At least I didn’t push a boat over a mountain.” An exasperated Herzog spins and spits, “What did you say?” “Nothing!” Penn mutters.

The details are best left discovered, from the irascible Scottish boat captain to Herzog’s so subtle self-mockery. (“He’ll be great,” he says repeatedly when meeting possible subjects. “I like his beard.”) As much a farcical take on the Blair Witch school as a resonant yet irreverent argument against the homogenizing entertainment industry by which Penn makes his fabulous living, Incident can hardly help copping out with a serpentine deus ex machina. But even that cheesy trump card is a vote for the supremacy of reality over corporate artifice.