This is some top-level trolling, sort of a massive in-person Rickroll.

The crowd is INTO THE MUSIC and just when they think the big finish is about to drop, they get ... upset. The roomful of groans that follow are just precious, as are all the waving hands that transform into middle fingers.

We'd love for this sort of thing to catch on, to get DJs everywhere to compete in a "Who can piss off the crowd the most?" contest. We especially like how the DJ hides in his booth. Dude knew exactly what he was doing. We applaud you, sir.