The infamous McRib sandwich returned to McDonald's restaurants Monday for another limited time engagement to the delight of fans everywhere. 

The McRib Locator website is overrun with confirmed sightings of the sandwich, some as early as Dec. 8, when a woman found it at a Los Angeles location. 


According to NPR, the McRib actually arrived later in the year than usual as it tends to make its appearance in October. 


Ian Chillag of NPR suggested that it is usually associated with Halloween because, "it's non-food wearing a food costume." 


The boneless barbecue pork sandwich, inspired by southern BBQ is fashioned to look like a rack of ribs. 


McDonald's first executive chef and inventor of the Chicken McNugget, Rene Arend, told Maxim in 2009, that the sandwich was brought to the menu due to a chicken shortage brought on by the extreme popularity of the chicken nugget that was introduced in 1979.


McDonald's originally introduced the McRib in 1982 and it has been on and off the fast food giant's menu since then. 


After being discontinued in 1985, it resurfaced 1994 as a seasonal menu item until 2005, when it was supposed to be retired for good. McDonald's even hold a farewell tour for the sandwich in 2005, as well as in 2006 and 2007, according to Fox News


The McRib then became available only at various regional locations. According to Yahoo Finance, individual restaurants can order McRib ingredients at any time and offer the sandwich at their digression. 


This sparked enthusiasts to establish tracking websites where people can report locations where the sandwich is available. The McRib Locator website in particular reported its first McRib sighting on Oct. 3, 2008 in Winner, S.D., Fox News notes.


The McRib has developed a cult like following that depends on its scarcity, according to Yahoo Finance. In 2010, McDonald's even began a "save the McRib" petition, encouraging fans to sign in support of having the McRib stay on menus for longer periods of time.


More recently, the McRib has been reintroduced overseas. It was available in Canada for short periods during summer and fall 2011, and was also Australia and New Zealand as the Atlanta Pork McRib during the 2012 London Olympics.


The sandwich sold out in New Zealand within days.