The line comes from Cyberpunk 2077, the 2020 open-world RPG by CD Projekt Red set in Night City. Short injury and death shouts from NPCs became popular clips outside the game because they are loud, isolated, and easy to reuse. This one spread as a soundboard and meme sound for any scene involving a sudden leg injury, fall damage, or a character being incapacitated, and it remains used because the panic is instantly readable without any context from the game.
About this sound
The panicked shout "Jesus Christ, my legs" from Cyberpunk 2077, used as a meme reaction for crashes, fails, and characters suddenly losing mobility.
A desperate male voice yells out in pain and shock, realizing something has gone terribly wrong with his legs. The delivery is frantic and over-the-top, with the panic rising instantly instead of building. It sounds like a genuine injury moment played for dark comedy, which is why viewers instantly get the joke. The clip lands best when someone falls, glitches, or gets launched, because the audio sells a catastrophic leg injury even when the visuals are silly.