Calling the Ronrico Rumkin a Halloween cocktail is a bit of a stretch since none of the ingredients has anything to do with Halloween.
The recipe for the Ronrico Rumkim, as it appears in the above 1983 ad:
1 oz. of Ronrico Rum
Dash of grenadine
Pour Ronrico Rum into a highball glass with ice cubes. Fill glass with orange juice. Add a splash of grenadine. Stir lightly.