George Condo at the Hayward Gallery. By Andrew Graham-Dixon.

What does George Condo think he is playing at? Hard to say, on the evidence of the Hayward Gallerys survey of his last forty years of activity. The show presents an ever-changing fairground gallery of enigmatic grotesques ranging from a pin-headed, goggle-eyed, shamefaced cartoon image of Jesus (2002), to a composite series of portraits of Queen Elizabeth II in which Her Royal Highness is presented as variously feral, buffoonish, rapacious, anodyne-beautiful and a Frankenstein assemblage of disjointedly reassembled body parts. God save anyone who looks like her. In fact, most people in Condos paintings do look pretty much like her, given a turn or two in his shape-shifting liquidiser of distortive styles.

Uncle Joe, one of a recent cast of characters/caricatures created in 2005 and here assembled under the rubric of Manic Society, is exemplary of the types that throng his seethingly dyspeptic world of snarling, disaffected, resolutely alienated individuals. There he sprawls, most definitely no ones favourite uncle, on a patch of what might be parkland: a half-naked, fag-wielding onanist, clutching a bottle of wine in one hand and balancing a glass of the same intoxicating liquid on his upturned right leg, all while blowing bubbles from the end of his stubbily erect and heavily thatched phallus.

Born in Concord, New Hampshire, in 1957, Condo began his career in New York in the 1980s. It was the era of Keith Harings funky graphic doodlings and Jean-Michel Basquiats assertive graffiti paintings, of Julian Schnabels smashed-plate pastiches of Cubist portraiture a time of anything goes, to which Condos magpie eclecticism and nervously ironic sensibility were well adapted. If he can be credited with adding one particular new ingredient to the stew that was Postmodern American painting in the 1980s and 1990s, it was a curiously lumpen attachment to the traditions of Old Master and classic modern painting. Most of the pictures on display at the Hayward amount to some kind of desecration of the past. Memories of Rembrandt (1994) morphs one of the Dutch masters solemnly morbid self-portraits into a snarling, potato-faced cartoon wraith. Lord Gorilla (2002) transforms Frans Halss Laughing Cavalier into a chinless, bewigged, grinning ape, wearing a lace ruff the colour and texture of pink blancmange. Elsewhere Condo colonises various corners of modern painting. Picasso doubletakes abound. American art is a target too. Big Red Jam (1992) looks at first sight like one of Arshile Gorkys proto-Abstract Expressionist works of the 1940s, a shimmering field of form and colour; on closer inspection, it is a jumble of orgiastically intertwined cartoon characters.

And so it goes on, this survey of a career built on level after level of parody and quotation: a veritable layer-cake of pastiche. What does it all add up to? Ultimately, not a great deal. History is full of great art that transforms other, earlier art. Manets Dejeuner sur lHerbe is a Venetian Renaissance pastoral by Titian joltingly transposed to a nineteenth-century Parisian park: a dislocation meant to expose what Manet saw as the loss of innocence in the modern, urban-industrial age. Francis Bacons image of the Pope screaming, in a glass cage similar to those in which the accused were confined during the Nuremberg trials, is a twentieth-century version of Velazquezs sinister seventeenth-century portrait of the scheming Pope Innocent X: an image of the evils of power, for an age that had seen the horrors of Auschwitz.

Such appropriations of the past add their own layers of present meaning in Bacons own words, they deepen the game. But whatever Condo touches, he makes shallow. No matter what his starting point, his end point is always the same: cartoon characters gurning, copulating, boozing, lost in the worlds of their own narcissistic excess. There is an aggressively petulant tone to his relentless mimicry, which suggests that his entire oeuvre is little more than the revenge of an artist who has very little to say on all those who had plenty.

But behind the iconoclastic bravado, a persistent anxiety lurks. Why would an artist anchor himself so securely in a past he seems to hate if he did not have a deepseated fear of his own works weightlessness? There is a single telling passage in the otherwise tedious catalogue to the Haywards show. It occurs in a hagiographic essay by critic Laura Hoptman: Condos playful tussling with the teleology of western painting, from Raphael through Cezanne, Picasso and de Kooning, has high stakes. Condo said recently, with not a hint of sarcasm in his voice: I would think the greatest fear of an artist is to be banished from the history of art; to be expelled from art history. It is a logical fear for him to have. When the art history of the future is eventually written, Condos name is unlikely to be found in the index.