The term scoobies comes from "Scooby Snacks" and refers to charred bits of herb and ash you may suck in while hitting a bowl. While unpleasant, they are no where near as bad as a flaming scooby which is a still smoldering piece of bud that will scorch the back of your throat.
"Dude, that bowl is almost kicked. If you hit it too hard you'll get some mad scoobies . . ."
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 wayjust call the Scoobies and they'll be on it stat. After dealing with their own adolescent issues first, of course.