The "ghost" makes unexpected appearances, frightening Mrs. Beakly, Webbie, Duckworth, the nephews, as well as Scrooge himself. Two of the resort's guest, an Italian race car driver and a wealthy socialite, raise suspicions that they may have something to do with the unforeseen spectre and that adds to the fun.
However, it is Scrooge's fight with the ghost that is the highlight of the episode. The animators have the rich duck rolling around and grappling with the invisible character atop a bridge that is also invisible. This makes for some fascinating animation as Scrooge is wrestling and tumbling over a moat, while engaged in battle, suspended over the moat.
Many kudos to the expert job of the animators.