The cartoon Scooby Doo has several ties with Buffy the Vampire Slayer. Xander calls Buffy’s group of friends the “Scooby Gang” for the first time in What’s My Line? (Part 1) as they have similarities with the young crime-fighting sleuths in the Scooby Doo cartoon. He says to Cordelia, “C’mon, Cordelia. You want to be a member of the Scooby Gang you gotta be willing to be inconvenienced every now and then.”
In Out of Mind, Out of Sight, Willow wears a white Scooby Doo t-shirt in this episode and in Beauty and the Beasts we see that she keeps her forensic tools in a Scooby Doo lunch box. In When She Was Bad, Xander wears a red Scooby Doo t-shirt.
Sarah Michelle Gellar appeared in two Scooby Doo movies, and Seth Green (Oz) appeared with Sarah in Scooby Doo: Monsters Unleashed. Sarah’s Buffy stunt double, Michele Waitman, also doubled for Sarah in Scooby Doo: Monsters Unleashed.
More Buffy/Scooby Doo trivia: In the movie Jay and Silent Bob Strike Back there is a spoof scene of Scooby Doo’s gang. The part of Fred was played by Marc Blucas (Riley Finn), Shaggy was played by Matthew James (who played the demon Merle in Angel) and Velma was played by Jane Silvia (who played the “conservative woman” in The Freshman).