THEATRE / Spirit levels: Paul Taylor and Judith Mackrell cast separate eyes on Caryl Churchill's The Skriker at the Cottesloe

The Skriker, Caryl Churchill's new play, is collaborative and multi-media, but it begins with a massive mouthful of words. The title character, a shapeshifter and death portent from English folklore, appears in the guise of a monstrous spider and spouts a long bewildering monologue in which the train of thought careers along in a madly associative, James-Joyce- meets-Professor-Stanley-Unwin fashion. A sentence like 'Bloody Bones in the dark dark dark we all go into the dark cupboard love all' jumps track from English faery to Eliot's East Coker to childhood terror to cliche, to tennis score. No wonder Kathryn Hunter, brilliant in all the Skriker's manifestations, looks at times as if it is language that's controlling her.

This damaged discourse is eloquent, however, of other, prior forms of damage and it gradually builds into an impassioned lament at the breakdown in relations between the human and faery worlds. In the old days, people used to 'leave cream in a sorcerer's apprentice'; now they hate and hurt natural spirits in their catastrophic abuse of the environment. In search of vengeance and love, the Skriker pursues two innocent young girls (one pregnant; one a psychiatric patient) to modern London. Shifting shape at every encounter, she obsessively endeavours to lure them to the underworld.

For me, the one unquestionable success of the evening is Kathryn Hunter's stunning performance. There's certainly wizardry in the range of identities this actress, with her tough little frame and throaty voice, assumes: from pushy American tourist to derelict old crone; from male psychotic to a sugary pink fairy on wobbly points who emerges from the innards of a sofa. The brilliance is in the unwavering psychological consistency that the performance achieves, so that all these impostures seem to be fuelled by the same devouring need to feed off people and yet to manifest an alien's misapprehensions as to what makes someone likeable.

It was only in the splendidly dubious revels in the underworld (candelabra with winking green talons as flames) that, to my mind, the attempt to create a broad sense of fairy-life came off. But the environmental dimension of the play is not entirely unembarrassing; if you believe in fairies, get green. In the end, it's the spooky-poignant imbalance in the Skriker's make-up that is the most haunting feature of the play: her amazing chameleon capabilities and her desperate dependency on creatures she can't quite fathom. Generating some fine comic riffs, it's a mixture that's bound to end in tragedy. PT

Caryl Churchill's fairy-tale for the 1990s is poised, as all good fairy-tales are, between the domestic and the grotesque, between reality and magic. Watching The Skriker we are as unknowing as most of the play's characters, having no idea what lies around the next narrative corner. What's partly responsible for the play's brilliantly shifting centre of reality is Churchill's language - skittering between sense and nonsense, throwing off rhymes, jokes, puns, obscenities and a chaos of associations. But the many sections of movement in the play, choreographed by Ian Spink, are also crucial. When they work best they seem to wriggle up through the cracks in the text, giving physical shape to the fantastic and inexplicable, suggesting other worlds, other ways of being than those of the ordinary speaking characters.

Much of the movement is closer to gesture and image than to dance, but Spink is particularly adroit at finding ways of capturing the play's collision between the real and spirit worlds. He also characterises individual spirits with a deft and vivid economy. There's a horribly spry malignancy in the way RawheadandBloodyBones springs and ducks across the stage, while the Green Lady drifts around with a dreamy, junkie kind of grace.

Less successful are the long dance sections for The Passerby. Though her slow silent wheelings register her as a mysterious, half- way presence between the real and spirit worlds, the choreography lacks convincing shape and purpose. Even here, though, you feel that the movement is indispensable, that the play's special language springs equally from words and dance.

But it's in Kathryn Hunter's Skriker that you're assaulted by the full richness of the combination. Hunter's power to change shape is as formidable and mysterious as the character she plays. With her tough, square, almost dislocatedly flexible body, she can hold a terrible, twistedly malevolent stance as the Skriker, while in her various 'human' guises she alters the whole colour, weight and line of her physical presence. In this performance, movement and language don't just complement each other, they are luminously inseparable. JM

In rep at the National Theatre (071-928 2252) to 26 April

(Photograph omitted)