The incident in Ayrshire on Sunday was caught on camera and shared on social media.
Police have confirmed a probe is under way.
The fight between rival families unfolded in Stevenston, where one of the clans is understood to be living in a car park close to the seaside town's beach.
Mobile phone footage taken by the attacking group shows men in a Transit van approaching the makeshift campsite.
Caravans and other vehicles are seen in the background as the gang speeds towards them.
One of them is then heard shouting: "Don’t ram! Don't ram the van!"
In the 35-second clip, another man is heard saying: "Out, now!" before he and a group of thugs race towards their victims.
One man can be seen swinging a spade, while another wielding a road sign follows on.
A third man is seen using a golf club as a weapon, while others have metal poles.
The footage cuts off before returning to show an injured man lying on the ground. Another clip then shows a brute using his weapon to smash a car window as a terrified driver cowers inside.
Many of the men, clad in hi-vis clothing, are filmed smashing up more cars and a caravan at the car...