This sound comes from Shia LaBeouf’s motivational performance video “Just Do It,” released online in 2015. The clip spread widely across YouTube, Vine-era reposts and later short-form edits because the delivery is intense, earnest and easy to parody. It stayed popular as a reaction sound for moments where someone needs a push, whether the result is impressive or disastrous. In meme culture, it often fills the same role as a bruh reaction, but with much more dramatic momentum.