McDonald's Szechuan sauce frenzy has left numerous "Rick and Morty" fans angry and disappointed after the fast-food chain failed to deliver the promised sauce and free posters in some of its outlets.

McDonald's is now reportedly facing threats of boycotts and class action lawsuits from the disgruntled customers following the one-day Szechuan sauce revival that the fast-food chain did in response to the sauce's resurgence in popularity due to an episode of "Rick and Morty."

Last Saturday, in one of the branches, more than a thousand customers camped out of McDonald's before it opened to acquire the condiment before everyone else, only to find out that the branch just had 70 sauce packets. The same situation was observed in other branches of McDonald's throughout the US. Some of the angry crowds even began chanting "We want sauce!" while fights broke out in other outlets.

According to Richard Adams, a former McDonald's franchisee, "There were some stores that just had 20 packets. Obviously the plan was executed by people who have no idea what goes on inside a McDonald's restaurant." Some of the lucky fans who managed to acquire Szechuan packets even put them up for auction, where a single sauce packet was sold for $274.99.

Dan Harmon, co-creator of "Rick and Morty" was also displeased at the gesture since McDonald's never officially tied the promotion to the series despite taking advantage of how it popularized the extinct sauce. Harmon went on to pick at the art of the Szechuan sauce promotion, implying that McDonald's also tried to imitate the show's art style, supposedly to rake in more fans of "Rick and Morty."

The outrage was acknowledged by McDonald's, and the fast-food giant has since promised to make amends. The famous and rare sauce will be a standard offering in McDonald's come winter, and they also assured the hungry fans that the high demand for Szechuan would be met with equal supply of the fabled sauce.

While McDonald's is working hard on fixing the Szechuan fiasco it caused, "Rick and Morty" co-creator Justin Roiland has distanced the show from the fast food chain, saying that they had nothing to do with the shortage and compelling the fans to be kind to the employees.