A video smuggled out of the Village Green Sunday evening shows hundreds of Oak Lawn residents breaking out into spontaneous mass dance.

The shocking video shows residents gyrating and thumbing their nose at authority during a free Hat Guys concert.

Even more disturbing is that Village Clerk Jane Quinlan, rebelling in her denim Capri pants, seemed to endorse the disturbing ritual during her rocking introduction of the band.

After the concert the Hat Guys took everyone prisoner with their great music and they all left on a UFO. Fortunately for some concert-goers they were wearing aluminum foil hats.

The next spontaneous mass dance on the Village Green will take place Aug. 24 featuring the band Hey, Jimmy.