"I don't need you," he declares, sacking Strassman at the climax of the act and going it alone. "Who's the fucking dummy now?" Other dolls get similarly short shrift from Chuck, especially "the losers, the ones who take drugs". He knows, because he sells the narcotics to them. Emu is a "slut puppet". As for the audience, Chuck spits on them: a great projectile gob that arcs through the air of the Beck's Spiegeltent, before entering a punter's beer with Exocet accuracy.
Ventriloquism was never like this with Lord Charles. It is Week 1 of the festival, so it pays to be cautious. There is a lot of hype around. Everyone is hungry for novelty (it's surprising how scant it is). That said, it already looks as if by the end of the three weeks the 36-year- old from Los Angeles will be one of only a handful of performers who "make a name" for themselves at Edinburgh this year. Or, rather, make a name in Britain. In America, Strassman has already chiselled out a career for himself with his peculiar blend of lacerating adult stand-up, calculating schmaltz, supernatural pastiche and hi-tech remote-controlled animatronics (Jim Henson meets Nasa: a friend of Strassman's from the space agency helped design the dolls). In Australia, Strassman fills 1,000-seater theatres. In Las Vegas, he plays at Caesar's Palace.
"I started with Chuck when I was 12," says Strassman, who must be one of the few children ever to have been offered ventriloquism lessons at school. "He's had that much time to grow. If you look at a picture of me then, holding Chuck, we both look younger. It's really sick." On stage, Strassman boasts of "a strange family" of puppets that spans from a pizza- eating alien called Kevin to three triceratops dinosaurs who dance to Queen's "Bohemian Rhapsody". The undoubted star, however, remains the wooden man-child Chuck. It was with him that Strassman made his big breakthrough in 1986, when he first performed the trick of leaving the stage and leaving the puppet to it. This was his passport to the top of the bill. Strassman's timing is exceptional. The robot technology is breath-taking (if that's the sort of thing that takes your breath). But it is Chuck that gives the show its distinctive dark edge. His eyes burn coal-red. His head swivles. "It's the time when the ventriloquist's puppet comes out into the audience and starts slashing and killing," he declares.
Strassman argues that what sets him apart from other ventriloquists are his characters' "back-stories". He knows the dolls' histories inside out, he says, something that can make speaking to him by turns unnerving and absurd. "Chuck claims he is hundreds of years old, that I'm not his first ventriloquist, that he's been travelling through the vaudeville shows and music-hall acts for centuries," he says, hardly stopping for breath.
"He knows he's a ventriloquist's puppet and he hates it. He's suffered from the Pinocchio syndrome and he wants to be a real boy. And he really can't. Or at least not yet. And so he has this pent-up anger based on that. And he's always taking it out on humans. He does know that I give him life. And so it's a symbiotic relationship. No matter how far he goes, he knows he always has to pull back. Because it's possible I might be able to give him life one day. And I do in the show. Or I might abandon him. There's fear of abandonment as well. That's pretty much Chuck's back- story."
Chuck is, in many ways, puppetry's answer to Beavis or Butt-head. "I used to think that he was sexually active. I used to do stuff like, 'Hey, honey, you into wood?' but then I realised he's a 12-year-old boy. He knows about sex. If you asked whether he was a virgin, he'd deny it. He's at that weird twilight between maturity and immaturity. He knows what's dirty, what's out there, but he hasn't really done it." This, perhaps, is what is most disconcerting about Strassman's show: innocence and experience threading their way throughout, the one blending into the other.
Even Ted E Bear, an almost cynically aaah-inducing hillbilly soft toy introduced to offset Chuck's malice, breaks off in the middle of one routine to lick his genitals. "What goes in hard and red and comes out soft and pink?" asks Ricky, Strassman's 18-month-old Cabbage Patch Doll of a baby character. "I know," Chuck says. "Bubble Gum." Which is a joke that Strassman probably doesn't use in his popular children's act.
n 10.30pm, Beck's Spiegeltent (venue 87). To 31 August (not 19,29)