Gather your ingredients: vanilla ice cream, bourbon, chocolate syrup, and milk. Let the ice cream sit at room temperature for about 10 minutes.

In a blender, combine about 2 cups of softened vanilla ice cream with 1-2 ounces of bourbon, 2 tablespoons of chocolate syrup, and a splash of milk. Blend on medium speed for about 30–45 seconds.

If the milkshake is too thick, add an extra splash of milk and blend for an additional 10 seconds until you reach your preferred consistency.

Pour the blended milkshake into tall glasses, leaving space at the top for garnishes. Top each milkshake with whipped cream, candy corn, and marshmallow 'ghosts'.

For a thicker milkshake, chill the blended mixture in the freezer for about 10 minutes before serving.