The two Smash Mouth songs featured in What's New, Scooby-Doo? "Gentlemen, Start Your Monsters" and "Reef Grief" were not made for the series (unlike many of the other chase songs). They were both on Smash Mouth's most recent album at the time "Get the Picture?" which featured both "Hot" and "New Planet" on it. Neither were ever released as singles off of the album, however, "Hot" was featured on "Hot Wheels World Race," a television show made to promote Hot Wheels. Both songs were written by Paul DeLisle (who has no relationship with Grey DeLisle, the voice of Daphne).
~ WildwindVampire ~