Back in 1998, McDonald's offered patrons a limited-time Szechuan sauce as part of a promotional push for Disney's new animated feature "Mulan."

After the hype for the movie died down, the sauce disappeared into relative obscurity — at least, until the first episode of season three of Adult Swim's animated sci-fi sitcom " Rick and Morty" premiered in April 2017. The show touted the sauce, and to say the public's interest was revived is a gross understatement; fans were stampeding and rioting for a taste.

A handful of savvy McDonald's fans recognized the phenomenon as a lucrative business opportunity, and rummaged around their homes in the hopes of finding an old Szechuan sauce packet. Many took to eBay to sell their old sauce packets: One jug of the discontinued sauce sold for a staggering $15,350 on eBay.