A blizzard of punches in the time it takes to blink an eye - it could only be the world record holder for the most blows in less than a second.
Young people on the latest Academy of Hard Knocks course in Aldershot were thrilled on Thursday to receive a special one-off lesson from mixed martial arts expert Ian Bishop, who holds the world record for 13 punches in a second.
The nine-strong rehabilitative group at the Maida Gym watched dumbstruck as Mr Bishop, recently inducted into the martial arts hall of fame, showed how to pepper punches on an opponent so quickly his fists become a blur.
Sam Rowe, a former prisoner who runs the project to keep young people with behavioural problems on the straight and narrow, said: "It was awesome.
"They got so much out of it. They'll be talking about it all weekend.
"We are exhausted, but it was so worthwhile. Ian Bishop is up there with Bruce Lee, he's a legend."
So keen was Mr Rowe to introduce the machine gun puncher to the 14 to 28-year-olds he is mentoring, he drove all the way to Barry in Wales to fetch him to Aldershot, before driving him all the way home after the session.
During the class Mr Rowe took a turn holding the pads for Mr Bishop, who founded the devastating Transporter System of fighting.
"He nearly knocked my arm off," he said. "When you get hit by him you know there will be another 12 coming."
Also on the pads was Mike Hobson, an ex-offender and participant on the course two years ago who now drops back in as a mentor.
The Academy of Hard Knocks runs three-month programmes for young men and women who have run into trouble, providing discipline and a means of letting off steam as well as gaining gym instructor qualifications.
Two weeks in, Mr Rowe said the current course was going well, but that funding for future groups was, as ever, far from guaranteed.