The Scooby Gang, or "Scoobies", are the names given to Buffy Summers and her friends and colleagues who assist her in her duties as slayer in the cult television series, Buffy the Vampire Slayer usually after they discover the existence of vampires and demons.
The Scooby Gang is needed to deal with supernatural and strange events in the Buffyverse. Namely Buffy, who can kick anyone's ass.
If trouble comes your way just call the Scoobies and they'll be on it stat. After dealing with their own adolescent issues first, of course.