The Scooby-Doo/Dynomutt Hour Season 1 Episode 5
The Headless Horseman of Halloween (Scooby-Doo): A Halloween party at the crane manor becomes a mystery when the headless horseman shows up.
The Harbor Robber (Dynomutt):
Blue Falcon run into Fishface, a fishy villain who plans to blend dry the rich cargoes passing in and out of big city harbor.
Serie: The Scooby-Doo/Dynomutt Hour
Episode Title: The Headless Horseman of Halloween / The Harbor Robber
Air Date: 1976-10-09