IT STARTED like any other sunny Saturday morning at Sugar Beat Cafe Murwillumbah, at the weekend.
People sipped cappuccinos, chatted and nothing really seemed out of the ordinary.
Except as this video shows there were a large number The Gym members in the area wearing green shirts.
When the music started, one local blue-shirted woman's reaction said it all.
Murwillumbah had been flash-mobbed.
The Gym owner Gad Rubenstein said it was the brainchild of member Tracy.
"Apparently during the morning it was quite busy at Sugar Beat, with our guys just sitting at tables.
"It went down really well: I think it was pretty casual and helped people relax a bit."
He said Riverside Thai's speakers were engaged for the music and was the only other party involved until the moment of action.
"Sugar Beat knew, but not exactly when, and I heard about it when I went down to Sugar Beat that afternoon.
"All of a sudden the music started, and they used some kind of signal but I can't remember.
"Tracy simply asked me before it was done 'I'd like to do a flash mob, and can we do it in our gym shirts?'
"It certainly helped to show what a friendly and social club we have."
"Guerrilla crocheting" is another local phenomenon Mr Rubenstein said he was aware of.
Though he is not sure whether the gym's effort is the town's first flash mob.
"I was walking past the police station one day and saw a very nice blue and white scarf crocheted nearby - actually sewn to the seat.
"And apparently there was once seen a crocheted snake near the swimming pool."
He said the event was typical of his member Tracy's tendency to "go out of her way" for people.
"She's one of those people who gives selflessly."