It's the circus, Jim, but not as we know it

It's been a decade since Rose and his troupe of misfit performers last descended on Edinburgh. They're back, and as well as the usual assortment of sharp objects, this time they've brought a script, suicidal goldfish and the art of anal painting, finds Kate Copstick

MANY have come to Edinburgh and become stars, some have come to Edinburgh and become perennial favourites. Jim Rose and his circus came to Edinburgh and became a legend. Through the last ten years, while Rose stayed away, the legend endured – broken glass and staple guns, Mexican Transvestite Wrestling and Chainsaw Football, dislocations, regurgitations and body fluids not normally spilt in the name of entertainment. Well now, as you may have already noticed, he's back. But be warned. To paraphrase Dr McCoy, it's the circus Jim, but not as we know it.

It's late July in New York. I am excited as I walk from Broadway/Lafayette station to join Rose and his new troupe for a day-long final rehearsal of the Edinburgh show. As I walk along Stanton Street I notice that a) there is a powerful smell of urine and b) every second person seems to be an amputee. I wonder if rehearsals are going badly, but apparently Stanton is always like that.

Arlene's Grocery Store is a gloriously grungy rock venue and it is here that the man who rescued the Freak Circus after it "lost a generation or so" and tore up the Edinburgh Fringe with it, is finessing his latest duet with damage. It is, he says, "a shock-rock opera with a faux-punk aesthetic".

The Billies are late and Chuck is in the toilet, the cast goldfish has committed suicide by jumping out of its bowl and Renee, a girl who makes Agyness Deyn look like Jimmy Krankie – and who does something worrying with a plastic bag and a suction machine in the show – has tertiary bedhead. But when the cry goes up "the scorpion is here!" the room cheers up.

Of course it is a real scorpion. The Whore of Babylon places it on her face and it goes walkabout in a kind of human-arthropod trust exercise. Jim arrives, calls the room to order, dons what he calls his "grandpa glasses" and starts a notes session.

The premise of the show is that the third-best heavy metal covers band in town are blown up trying to break the "most pyrotechnics used in a show" record. They go to heaven – which they hate, because they are 1980s rockers and want to go to hell… "Where are we with our tampon dilemma?" Jim demands. He is both directing the show and playing Satan. Satan has much to learn. The tampon goes down for an extra rehearsal.

"Pregnant lady, Billy?" says Jim. Billy, once a "featured toddler" in 1980s movie Three Men and A Baby, is now playing the deceased band's lead singer in a performance style that is half Mick Jagger and half Max Wall. He looks up. "You hit her too hard," he says.

Rose is a good director. He has to be. These rehearsals have been a leap in the dark for this cast. The trust they have in this wiry, intense man is impressive, and richly repaid. One month ago this show was a comedy rockfest called Stairway to Hell, brainchild of Randy Weiner of The Donkey Show fame. Then he had the idea of persuading Jim Rose to play Satan and to turn the fairly funny rock romp all "Rosey". Rose had one month to take a band, two actors and a couple of girlie dancers and turn them into "The Jim Rose Circus: The Musical".

It is, arguably, his greatest stunt to date. There is a chainsaw on the floor of the rehearsal room, and I feel comforted that Jim has included some of his classic props. "Demon!" Jim says, and a sweet boy with a slightly anxious look leans into the circle. "We talked about when you are f***ing the sheep." The sweet boy nods. "You've got the cape, the blocking … there's a lot to think about!" The sweet boy grabs his sheep and a short choreographic session ensues.

Suddenly Jim looks up. "Honey? Go take that scorpion somewhere else, you're just distracting everyone!" The Whore of Babylon (aka Bebe, Jim's wife and the only other circus professional in the show) removes the scorpion from her face and goes off into a corner. Now attention turns to the drummer. "We all know what happened when we were supposed to light your crotch on fire!" The group shrugs and laughs and nods. "What are we going to do about that?"

The afternoon wears on. We fix the problem with the rat trap and Lars Torture's tongue, we check the knife for the self– harming display, Jim checks his broken glass and his razorblades and we all blow up plastic sex dolls. The cast are obviously loving their new-found skills to thrill. And Jim is walking a directorial knife-edge between discipline and protection. "We do not want to ad-lib in this show… we're not there yet!" he admonishes Billy – a performer who still displays much of the "featured toddler" he once was.

"I am doing the show because I want to remind the people what the Fringe used to be before it became what it is," he tells me. "I am," he continues, puffing hard on a Marlboro, "at a point where I don't have to do anything I don't want to. I am at a point where you could offer me a million dollars to do something and if I didn't want to do it I wouldn't."

This is true. He has toured with Nine Inch Nails and Marilyn Manson, has had his own TV show, has starred on The X-Files and has had Homer run away to join his circus in The Simpsons. He has his own PR company, has graced the cover of the Wall Street Journal, is US business's posterboy for "thinking outside the box" and relaxes by playing a lethal game of poker. "But forget all that," he once said to me. "My proudest achievement is being the hottest ever ticket at the Edinburgh Fringe." So he's back.

This show is fired by Rose's passion for theatre, for punk as an art form, not a pop style, and for shock and outrage as colours in the creative spectrum, not gimmicks. Rose's cast of "babies" are learning how to love playing with some dangerous toys. Ridiculous as this may sound, what he is doing with this cast is possibly the most empowering experience of their lives. They are loving it – and really, who wouldn't? As a performer, how often do you take your audience's breath away, give them a genuinely visceral reaction?

Trash ("you get the idea better when I'm in spandex"), the band's very impressive lead guitarist, gets that Brian May swagger when he riffs. But he really lights up when he slams his "third thumb" in a racoon trap.

Billy, meanwhile, is a charismatic actor who is grabbing his opportunity to be a rock god with two hands. But when Jim announces that producer Randy thinks Billy should be the cannonball guy he is obviously thrilled and even gets a round of applause.

At 12pm, Rose is working on "how do we establish goofball?" with his Demon. At 12:30pm he is commiserating with the company sound guy who has been refused permission to leave the country because he is behind on his child maintenance. At 1pm he is choreographing the Security Guard stunt with Barracuda – a man with the torso of a prop forward and the face of a cheeky cherub. There is a public dress rehearsal at 5:30pm and then Rose gives his cast the "Edinburgh First-timers Talk" that begins "You've never been anywhere like it …"

Afterwards he goes to eat tacos, half-smoke cigarettes and talk to Bebe about anal painting. Bebe is a charming whippet-like woman who exudes calm. Essential, of course, when you are accessorised with live scorpions. Bebe has been teaching a tall, almost unacceptably beautiful dancer called Devon to paint by blowing paint out of her anus. Really. She is gaining in confidence all the time, Bebe says. Having seen the rehearsal, I would say this looks like her blue period.

Jim is fretting about all the things any director would fret about… and then a few more. That tampon dilemma is still not resolved. And he is worried about Billy being Mr Cannonball. He and Billy need, he tells him, "to establish a comfort zone". They both need to know exactly what they are doing.

It's 2:30pm. The run begins. It is strange to see the show with the stunts mimed: what is Bebe pulling from her nether region? What happens to the girl in the plastic bag? The music is terrific – The Scorpions, Aerosmith, AC/DC, Sabbath. If this show doesn't rock you, nothing will.

Then Jim decides to rehearse Billy's cannonball moment and disaster strikes. As the plate breaks, Billy is pounding out vocals on Rock You Like A Hurricane and his "rock arms" get in the way. He is cut – not badly, a bouncing bit of ceramic doesn't do much damage. But Billy is hysterical and Jim is distraught. The rehearsal is stopped. There is discussion of doctors, stitches, ER.

Jim looks to be on the point of opening a vein and offering an instant transfusion when we actually get to see the wound. A couple of butterfly strips and a bandage later we decide the show must go on.

As I watch Jim apologise over and over to the boy, I feel sure that the most damage done has been to his confidence in running this show with a cast of newbies.

At 4:30pm, Jim is chain-smoking outside. The sweet Demon is standing on the sidewalk, dressed in red Spandex, face covered in fake blood, revving up a chainsaw. The Lower East Siders walk past, chatting. You have to love New York.

It's 5:15pm. Jim is scattering little splashes of ammonia in the corners of the bar-room. An old trick, he tells me. Makes the place smell like the floor has been washed so people feel OK about sitting down on it. At 5:30pm the show is on. The audience whoops, screams, gasps, groans and laughs and laughs and laughs.

Jim's Satan is truly from a different realm from the newly-dead rockers. I feel I am watching life imitating art, or possibly vice versa. In the same way the on-stage rockers think that hell is just a big party where everyone is badly behaved, the actors just now are enjoying simply "doing" the stunts. Just as you can see from Rose's Satan that the rockers are going to get more than they bargain for once they are really down in hell, I itch to see this show in a year, when these guys are "owning" those stunts, wanting to push things a little further, wanting more screams and generally nurturing their inner circus freak.

And if there is a modern-day Moira Knox out there, don't worry, there is plenty to be outraged at, plenty to warrant advocating a ban in the name of all that's Presbyterian. There is nudity of every conceivable (and one inconceivable) type; there is sex, drugs and, of course, rock'n'roll. The religious will be frothing at the mouth and goldfish lovers less than pleased. Add to that some of the most appalling jokes on the Fringe and – of course, anal painting – and the late Councillor Knox is undoubtedly birling in her grave. Jim wouldn't have it any other way.

• Jim Rose Circus is at Udderbelly's Pasture until 25 August, 11:45pm.