It is getting increasingly difficult to refer to Big Bang as a boy band, with the artistically challenging work contained on the "MADE" series of singles, released in sets of two at the beginning of each month for the last four months until all of the songs from the group's first full-length studio album in Korea in seven years were featured.

Emanating the confidence, skill and polish that made them international superstars, Big Bang took the world by storm with the "MADE" series, topping singles charts in several Asian countries and racking up millions of YouTube views in the process.

But on the song "Zutter," released Wednesday as the final installment in the series (or as the "E" in "MADE") before the full album is released on Sept. 1, is arguably the group's most blazing and edgy single to date. Featuring only the rapping of bandmates and childhood friends G-Dragon and T.O.P, "Zutter" is as danceable as anything in the Big Bang catalog.

In addition to their side project "GD&TOP," G-Dragon and T.O.P have both a musical and personal history that predates Big Bang. Their chemistry on the mic over a beat they wrote with longtime producer Teddy, is tangible proof this kind of personal connection makes a difference in music.

And though many hardcore Big Bang fans, known as V.I.P., might find the mere suggestion that a song that is practically a GD&TOP track could be among the group's best to be anywhere from blasphemous to imbecilic, the combination of the pitched tom-tom samples of Diplo or The Neptunes with the Dirty South hi-hat sixteenth notes so popular in South Korean underground rap is an undeniably inventive choice.

More and more, Big Bang seem to be making music for themselves, or perhaps simply music for adults. Doubling down on this more mature concept is the music video for "Zutter" which features T.O.P and G-Dragon, mobbed up in brightly colored suits, tied up and tortured in one sequence and getting into a urine fight in the men's room in another.

I don't remember The Backstreet Boys ever doing that.

Watch the music video for the new Big Bang single "Zutter" RIGHT HERE