One of the funniest ad campaigns of 2015—Australia's "The Boys" campaign for Bonds underwear, starring a pair of chatty testicles—returns in a big way for 2016 with a seven-story-high weather billboard in downtown Melbourne in which the lads react in real time to cold, warmth and wind.

The agency, Clemenger BBDO Melbourne, explains:

When it's cold, the boys shrink towards the top of the billboard, and when the weather heats up they descend and hang freely. The boys get swung about whenever the wind blows, too.

The board is now up at Melbourne's iconic Bourke Street Mall. Check in out in action:

It's a fun and—OK, yes—ballsy board that combines playful creative with nifty high tech.

"While we pioneered a technology more than two years ago to serve up advertising based on average temperatures, this campaign takes it to a whole new level using live RSS feeds," says oOh! media CEO Brendon Cook says. "Through our ability to innovate and Clemenger BBDO's excellent creative, the campaign will drive much greater consumer engagement than previously possible."

"There's a lot your boys have to go through and that includes changing climates during the day," adds Clemenger BBDO Melbourne creative director Ant Phillips. "So we designed a billboard that not only displayed the weather, but also showed men how their 'boys' would be affected."

Oh, and there's also some new TV spots, which you can check out here: