We were tipped off by Jan Eric Andersson that the McRib has arrived in South Korea. Provided was the following photo from what appears to be a release party there for the sandwich and related contest.
A peek at the South Korea McDonalds website confirms the availability.
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Their YouTube clip showing their advertisement has the patty taking a rather odd fall from above.
It appears that they are running some type of contest with what they are calling the “Lucky Burger”. Having the McRib is lucky enough, adding a contest makes it a Very Lucky Burger. See their contest page here.
It appears they will be serving this McRib variant through January 29.
The McRib has been reappearing in Korea for several years now as a seasonal item around new year, where as your post mentions it’s marketed as the “Lucky Burger” or “Prosperity Burger” as its increased length is meant to be symbolic of a long and prosperous new year. This year it had a premium version that included a hashbrown patty too. Here’s McDonalds Korea thanking 2 million “Prosperity Burgers” sold!
https://www.instagram.com/p/C2_Na9Vh8em/