The shout comes from Cristiano Ronaldo's signature goal celebration, in which he leaps, lands with his arms out and shouts Siuu to the crowd. Fans quickly turned the chant into a stadium and social media staple, copying it after goals and in short football clips. Editors later boosted its volume, removed the buildup and repurposed it as a jumpscare, a twist that works because the sound is instantly recognisable even without the football context. That mix of familiarity and sudden loudness keeps it popular in memes, gaming videos and reaction edits.