What's New, Scooby-Doo? premiered in 2002 as the first Scooby-Doo series of the 2000s, following Mystery Inc. in a modernised format. Simple Plan recorded its theme, replacing the classic 1969 melody with a pop punk sound aimed at a new generation. Clips of the song later spread on TikTok and YouTube in nostalgia edits, episode rankings and Cartoon Chase montages. Its direct title hook, familiar characters and early 2000s energy have kept it recognisable long after the series ended, making it the version many younger fans associate with Scooby, Shaggy and the gang.