"Saw" movie fans have no trouble believing that homicidal freak Jigsaw is really out for their blood.
But do they know it's for a good cause?
While slashing its way to $247 million at the box office, the studio behind the "Saw" film franchise has helped the American Red Cross collect 30,000 pints of blood.
With "Saw III" opening Friday, Lionsgate Films has arranged blood drives across the country.
"We'll be at 30 cities opening day," producer Oren Koules said to ABC News Radio's Dave Alpert. "And when they donate blood, they'll get a 'Saw' T-shirt."
The blood drive began with the first film in 2004, with the Red Cross collecting 4,249 pints of Jigsaw's favorite bodily fluid.
"People have equated 'Saw' with blood," Koules said. "And we thought if we could turn that into something that's good, it's great."
The film's star has already made a visible donation.
The blood of Tobin Bell, who plays Jigsaw in the movie, was mixed with the red ink used on promotional posters.
Add that chilling, little detail to movie posters and promos that have featured severed body parts and blood-spattered torture devices, and "Saw III" is off and running for another Halloween assault at theaters.
"We were doing a really neat Tobin-only poster, and they came up with the idea he would put his own blood into the red ink. … And they had to have people check," Koules said. "It's never been done before."
One poster, with signatures from the cast, will be auctioned online. That money also will go to the Red Cross.
In the new film, Jigsaw kidnaps a doctor to keep himself alive while he watches his new apprentice put an unlucky citizen through a brutal test.
As the advertising promises: "Suffering. … You Haven't Seen Anything Yet!"
Not to ruin an ending that's bound to be unhappy, but, whatever happens, another sequel is already in the works.
"We've actually worked on the fourth one already, and I think we kind of have this universe mastered," Koules said. "We're really excited about 'Saw IV'."