MASON CITY, IAThe ghostly shade of Marlon Brando appeared before Carl Wilkins Sunday to urge the 36-year-old auto-body technician to devour an entire two-pound cheesecake. 'He was really intense, rubbing his head and jutting out his jaw and saying, over and over, 'Finish it off,'' said a slightly shaken and dyspeptic Wilkins. 'I'd forgotten how good Brando could be.' After Wilkins swallowed his last bite, the apparition smiled with an orange slice in its mouth and disappeared. 