The greeting comes from the Budweiser Whassup adverts that aired from 1999, based on Charles Stone III's short film True, where friends call each other just to shout the word back and forth. The 2000 parody in Scary Movie pushed it further, with characters stretching the shout and sticking out their tongues, and that version became the template most people imitate. It later resurfaced as a classic scream meme in early soundboards and reaction edits, and the elongated wazaaaa spelling keeps it alive in chats, streams and short videos today.