Hoagy first appears when he and Dr. Terminus arrive in Passamaquoddy on their sail-powered traveling wagon, having escaped from what is either a police force or a lynch mob. Hoagy disguises himself as some volunteer patients Dr. Terminus performs "miracles" on to win the townspeople over.
Dr. Terminus and Hoagy are initially skeptical of the existence of Elliott the dragon when Lampie tells them at the local tavern, despite Hoagy later seeing him in his cave with Lampie.
Later on, Dr. Terminus sends Hoagy to Elliott's cave to lure him to the boathouse. Once he arrives, the townspeople drop a large fishing net onto him and try to restrain him while Dr. Terminus attempts to kill him with a harpoon. After a fierce struggle, he breaks free, scatters the townspeople, and rescues Pete from the Gogans.
In the end, Dr. Terminus and Hoagy meet their defeat when, in an effort to harpoon Elliott, Dr. Terminus' leg is caught in the rope and he is sent catapulting through the ceiling while screaming a "Goofy holler" as he goes through the roof, ending up dangling upside down near a telegraph pole with Hoagy at his side. In a last-ditch effort, he tries to offer buying Elliott's "spare parts" (i.e. loose skin and hair), to which he declines and proceeds to destroy their traveling wagon, thus ending their scamming business for good. It is unknown what happened to them after that, though it is most likely they were arrested.