In the English release of Street Fighter II, one of Ryu's quotes to defeated opponents is "You must defeat Sheng Long to stand a chance." "Sheng Long" is a mistranslation of Ryu's flying uppercut move Shōryūken (昇龍拳) stemming from the first two Japanese characters meaning "shēng lóng" in Chinese pinyin. As a result, players mistakenly thought that Ryu was referring to a person named Sheng Long instead of his Shōryūken, and that he was a secret playable character.

Amidst a swarm of fan mail to gaming publications asking how to unlock Sheng Long, the American magazine Electronic Gaming Monthly published a guide to fight him as a secret boss for their annual April Fools' prank in 1992. Photoshopped screenshots of Sheng Long fighting Ryu were created by editor Ken Williams, who also wrote "ridiculous requirements" to find him that were meant to imply he was not real, but were actually attempted by players. In response to complaints, they revealed at the end of the year that Sheng Long was a hoax, and expressed surprise over it gaining worldwide coverage as other publications in Eurasian countries reprinted the guide without their permission.

Sheng Long was brought back for a second April Fools' prank in 1997 in response to rumors that he could be in Street Fighter III, creating hand-drawn art of him and claiming he was the localized version of the real non-playable character Gouken. Despite adding more obvious clues to it being a prank, according to the magazine's June 1997 issue, this second prank was so convincing that Capcom of America allegedly fell for it and called their Japanese headquarters to ask why they were not told he was in the game.

Sheng Long left a continuing influence on video game hoaxes and the Street Fighter series, leading to a scrapped official appearance in the game adaptation of Street Fighter: The Movie, and Capcom pulling their own Sheng Long pranks in 2008 and 2017. In 2023, Sheng Long made his first canonical appearance in the series in Street Fighter 6 as a non-playable opponent using Ryu's fighting style, and can be fought in the World Tour mode after completing the game.