Mulder and Scully stay at the Gulf Breeze trailer court. Here, they meet the distrustful manager Mr. Nutt (Michael J. Anderson), and Lanny (Vincent Schiavelli), an alcoholic with an underdeveloped conjoined twin named Leonard. The agents hear a story about the legendary Fiji mermaid, a common sideshow act in the 19th century that generally turned out to be a monkey with a fish tail attached — the "humbug" referred to by the episode's title. Despite Scully's usual skepticism, Mulder is intrigued because of what look like simian tracks left by the mystery attacker.