The Scooby-Doo Show Season 3 Episode 6
The gang heads to Scotland to help Velma’s friend Aggie MacDuff, who’s ancestral castle home, which she’s turned into a tourist attraction, is being haunted by the ghost of her great grandfather Finnyan MacDuff, who in turn has summoned the Loch Ness Monster to help him scare away potential tourists.
Serie: The Scooby-Doo Show
Episode Title: A Highland Fling with a Monstrous Thing
Air Date: 1978-10-14