If you believe in such things, you might think that Ghost The Musical is itself haunted.
Perhaps a mischievous poltergeist is at work, moving objects about on the stage.
It seemed like that on the first night of its UK tour in Cardiff, when a sofa had a mind of its own. Computer controlled and on tracks, it failed to appear at the start of a scene.
It then came on late, before slowly moving across the stage, stopping at random points along the way.
The cause is more likely to have been a technical, rather than a supernatural, hitch in the most technologically complex show to hit UK theatres.
And the gremlins in the system have been rooted out.
It’s the musical version of the 1990 hit film, which starred Patrick Swayze as the banker who is killed during a mugging but who returns as a ghost to warn his girlfriend Molly (Demi Moore) that she’s in danger. Whoopi Goldberg won an Oscar for her role as psychic Oda Mae Brown.
The stage production, with songs by Eurythmics guitarist Dave Stewart, opened in Manchester in March 2011 before moving to the West End and Broadway. The UK tour began last month and arrives at Wolverhampton Grand Theatre next week before playing for three weeks over Christmas at Birmingham’s New Alexandra Theatre.
Taking the high-tech set on tour in 10 articulated trucks is a challenge. It includes seven heavy LED video walls, displaying a total of 172,000 LED pixels. They can instantly take audiences from an office to a New York subway train.
There are 810 lighting cues and 746 sound cues in the show, meaning everything has to happen at exactly the right time.
Ghost also has some clever and spooky special effects – a spectre appears to walk through a door at one point.
The illusions are designed by Paul Kieve, who was responsible for many of the magic props and sequences in the Harry Potter films, and are executed by assistant stage manager Matthew Breen.
Matthew, from Sutton Coldfield, says: “We had a very limited amount of technical rehearsal time before the first night of the tour, so a few things went wrong.
“We’ve ironed them out now. This is such a highly technical show – for example, 90 per cent of the scenery is automated, not moved by hand. The scene changes need to be so slick.
“The video walls which fly in and out are used to create locations and atmospheres. Everything is meticulously timed – the actors dancing on stage are synchronised with the people dancing on the video behind them.
“A few years ago, video wasn’t an element in theatre, but now you have a whole team of people looking after it. It’s just as important as lighting or sound, and we use it to such an amazing effect.
“There is very little margin for error. It’s crazy backstage during a show. The wings, where everything happens, is run like a military operation.”
There’s a wardrobe department in the wings as there are so many quick costume changes for the cast. One, in which jackets are swapped for sparkly numbers, involves an army of dressers lined up to change outfits in just six seconds.
Another challenge will face the crew when they come to Wolverhampton, as it is the first raked stage they encounter.
“Anything on wheels will have to be modified,” says Matthew. “And we’ll tweak the lighting so we don’t spoil the magic.”
Matthew is only 23 and trained at Birmingham School of Acting. He was among the first group of graduates of its new three-year stage management course.
He’s previously worked on Legally Blonde, Steel Magnolias and pantomimes at Birmingham Hippodrome.
“I really like to know how things work on a show,” he explains. “Especially one like Ghost.
“The attention to detail is incredible. We use real American newspapers and all the candy in the vending machine in the subway station is American.
“They use the actors’ real photos on their driving licences and social security cards. And for the famous pottery scene, we use a real pottery wheel and Molly makes a real pot using clay and water.”
“It’s the moment that terrifies me every single night!” reveals leading actress Rebecca Trehearn, who is dark-haired but wears a blonde wig as Molly to fit in with the promotional posters.
“They sent me off for pottery lessons but it’s surprisingly difficult to do. I have a time limit and I’m quite emotional and worked up at the time.”
“I love it when it goes wrong,” laughs her co-star Stewart Clarke, who was born in Worcester and grew up in Solihull.
“You can see when Rebecca’s thrown the clay wrongly because it goes all wobbly on the wheel.”
Handsome Stewart is only 22 and not long out of drama school but does well in the leading role. He’s not the only Midlander in the cast, as the ensemble includes Robert Knight from Halesowen and Birmingham-born Kimmy Edwards, both 24.
Kimmy, who went to Thomas Telford School, is thrilled that she gets to stand in as one of Oda Mae’s sisters during the Wolverhampton run.
Robert, a former pupil of Leasowes High School, says of the show’s technical glitches: “We haven’t had any major problems since the first night, which was nerve-racking. Having scenery move about and in the wrong place keeps you on your toes!”
* Ghost The Musical comes to the Grand Theatre, Wolverhampton, from June 4-15. For tickets ring 01902 429212 or go to www.grandtheatre.info. It plays Birmingham's New Alexandra Theatre from December 17 to January 5.