Davie504 is the online name of Italian bassist Davide Biale, who built a large YouTube following with virtuoso slap bass covers, challenges and comedy music videos. He calls his audience slappers, a reference to the slap technique central to his playing, and what's up slappers became his regular opening line. As his catchphrases were clipped and shared across meme and soundboard communities, this greeting spread beyond his own uploads and became a standalone cue that viewers associate with bass playing, overconfidence and playful showmanship.