Wild Brawl Breaks Out at Annual Florida Lake Party

When you throw an event called "Mayhem at Lake George" ... well, you gotta expect some mayhem and this year's get-together was true to its name.

Video has surfaced from the event in Volusia County, Florida, in which a massive fight breaks out ... aquatic style.

It got really bad ... one guy was seriously injured. He was taken to shore and flown to a hospital. We don't know his condition.

No surprise ... alcohol was involved, and apparently lots of it. The Sheriff said, “People are just out there to have a good time, but like anything else, when you have a huge concentration of people like this and you have alcohol involved, you do have some incidents."

It's pretty wild ... you see a guy punch another dude in the face and another guy is tackled into the water ... before things erupt into pure chaos.

There were arrests ... 5 of them. The offenses were predictable ... disorderly conduct and boating under the influence. There were also nearly 40 boating citations.