TWO huge paper slinky spirals, one red, one purple, and a great yellow balloon flying above them. The flimsiness and colour of Chinese lanterns, and a yellow moon. Or girl and boy and a ball. And now the ball is heading towards the audience in Galway's Big Top, who shriek and recall for it, five year olds and 50 year olds alike. This is Mummenschanz, and don't ever say again that the Swiss are good for nothing but cuckoo clocks.

On the go for more than two decades, Mummenschanz (Bernie Schurch, Floriana Frassetto and Andres Bossard, the first two of whom created the Galway show) began in the school of Jacques Lecoq, and then moved on to develop their own form of illusion. Their masks are changing ones, and they have scoured both their minds and the stores of the world for new materials.

Two men meet with grey putty masks, which they move and manipulate, and then get buried in each other, like two cream pies. Huge Michelin man balloon suits are pulled into shapes, from King Tut, to Fifties mannequin.

Strangely, because they have lost the shape of reality, they ground themselves in stereotypes because stereotypes are the rough outline of personality with which clowning plays. And so the girl boy stuff is the best. The plug and the socket unite in a blaze of light (two pin plugs, you understand, no nasty stuff here). Two vast spinnakerheads, one pink, one blue, dance back and forth, always, tragically, ballooning away from each other as they rush together.

Schurch and Frassetto, as well as John Murphy, are lithe and graceful, but really the bodies disappear completely behind the illusion, and would disappear more fully were the Big Top's lighting facilities better attuned to the players' needs. This is the true theatre of illusion, which exchanges the body for the body of the emotions, and it demands to be seen.