CHICAGO -- Rappers can be pretty adventurous when it comes to fashion (think: Kanye, A$AP Rocky and kilts) -- but the open-air, anything-goes setting of a festival seems to be especially liberating for an MC when it comes to stage style. That seems to be what fuels Kid Cudi.

Cudder made waves when he debuted a cropped crimson gym top at last year's Coachella.

But fans at Lollapalooza on Saturday expecting more bare mid-riff from the "Man on the Moon" MC were treated instead to a fashionable about-face that was more Dad than daring ... which is kind of daring in itself, no?

All about this throwback look. And this 'Calvin Klein jeans ad circa 1987' pose made me particularly happy.

Was Michael J. Fox's Back to the Future wardrobe Cudi's inspiration?

Cudi's comforting paternal style was ALMOST as good as when he jumped into the crowd for an epic performance of "Pursuit of Happiness." Swoon.