This comic fable about making an Exorcist-like horror movie has its moments--and, heaven knows, may not overestimate the gross appetites of a portion of the American reading public. Each Blatty (Legion, 1983, etc.) paragraph drools with faux- movie dialogue and highbrow asides (to The Magic Mountain, Shakespeare, Emily Brontâ, Dickens, Prince Miskin, etc). The most memorable figure in the book is reminiscent of the Nazi playwright from the Mel Brooks film The Producers, rendered here as a demented film projectionist in a Prussian army helmet, Jesus Machtmeintag (Makemyday). His scenes are particularly droll. `` `Go avay!' shrieked the deep German voice hysterically. `You haff zer wrong man, I tell you! I am innocent!' There followed adamant denials that he'd ever gone bowling with Joseph Goebbels, weekend flying with Rudolph Hess, knew anything whatever of letters of transit, or had ever defaced Casablanca posters to suggest the film's hero was Conrad Veidt. `All lies!' bellowed Machtmeintag in a fury.'' The scenario: Celebrated director Jason Hazard has been in the dumps for three years when archfiend/studio head Arthur Zelig hires him to direct the film version of Jonathan Drood's bestseller, The Satanists. Hazard has run off with Zelig's ex-wife, leading actress Spritely God, and Zelig schemes to make sure that The Satanist will be a colossal bomb, blowing Hazard completely out of the water and driving Spritely back into his bed. She, however, is so aghast at Drood's script that she demands the studio be exorcised. Various exorcists show up throughout, including Don Rickles, who fails to exorcise Spritely's cat, Barbra, which sings like Streisand and turns into a gigantic rat on a levitating bed. Perhaps Mel Brooks will direct the movie? Echoes of musty old Max Schulman novels, with some laugh-out- loud lines about Hollywood lost in extra-luxuriant false classicism and excess.