For a brief moment in time, the U.S. had a trade relationship with an African kingdom famed for an illusory metal called vibranium.

Officials with the Department of Agriculture listed Wakanda as one of America's trading partners on a tariff tracker website while testing some new software. The unnamed USDA staffer who added Wakanda to the tariff tracker also noted that the imaginary African country has traded ducks, donkeys, sheep, dairy cows and other livestock with the U.S.

The USDA took down the entry Wednesday after the inevitable comments from social media. "The Wakanda information should have been removed after [software] testing and has now been taken down," USDA spokesman Mike Illenberg said in a statement.

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Wakanda is a fictional east African nation created in 1966 by Marvel Comics writer Stan Lee and artist Jack Kirby. Wakanda is also home to one of Marvel Comics' most recognized superheroes — the Black Panther. Marvel Studios' 2018 Black Panther movie, starring Chadwick Boseman as the title character, generated more than $600 million in ticket sales, won Academy and Screen Actors Guild awards, and became one of the studio's most popular installments in the Avengers franchise. A Black Panther sequel is slated to be released in 2022.

In the comics, Wakanda houses Earth's largest deposit of vibranium, a metallic ore that can manipulate kinetic energy. The metal was sewn into the Black Panther costume. Less widely known is that it was also used to create Captain America's iconic circular shield. Although vibranium is abundant in Wakanda, it is characterized as an extremely rare and valuable metal throughout the rest of the comic book storylines.

Francis Tseng, a fellow with research firm Jain Family Institute, saw the USDA's Wakanda listing Wednesday and tweeted his reaction.

Wakanda is listed as a US free trade partner on the USDA website?? pic.twitter.com/xcq1OFTIPh — Francis Tseng (@frnsys) December 18, 2019

"For what it's worth, the U.S. would no doubt try to liberalize Wakanda's markets and flood it with cheap subsidized corn," Tseng joked.

Others who saw the USDA trade list questioned whether American officials were making wise trade choices — livestock over vibranium — with Wakanda. "Did anyone on the USDA actually watch Black Panther?" asked Twitter used Harold Nyikal.