Brands leaning hard into nostalgia with call-back products, packaging, and offerings are likely to profit off of Millennials' yearning for all things yesterday. The latest proof: Hot Topic has “struck retro gold” with their adult-sized Underoos. For the uninitiated, Underoos were the superhero themed undies extremely popular with kids in the ‘80s. The new adult line has almost completely sold out online within 24 hours of being announced. (Adweek)