At Will’s wedding party, Edward Bloom recalls the day Will was born, claiming he caught an enormous catfish using his wedding ring as bait. Will, having heard these stories all his life, believes them to be lies and falls out with his father. Three years later, Edward is stricken with cancer, so Will and his pregnant French wife Joséphine return to his childhood home in Alabama to spend time with his father. Edward’s life is told through flashbacks, beginning with his encounter with a witch in his hometown, Ashland. She shows him his death but he reacts to it without fear. As he grows into adulthood, he finds his home too confining, and sets out into the world with a misunderstood giant, Karl, who has come to town with a traveling circus.
Edward and Karl find a fork in the road and travel down separate paths. Edward follows a path through a swamp and discovers the secret town of Spectre, the cheery locals claiming he was expected. There, he befriends Ashton poet Norther Winslow and the mayor’s daughter Jenny. However, Edward leaves Spectre, unwilling to settle down but promises Jenny he will return. In the present day, Joséphine speaks to the bed-ridden Edward and asks him to tell her the story of how he met his wife Sandra, with Will listening outside the door. Returning to his reminisces, Edward reunites with Karl and they visit the Calloway Circus, where Edward falls in love with a beautiful woman. Karl and Edward get jobs in the circus where the ringmaster Amos Calloway reveals to Edward one detail about the woman at the end of every month.
Three years later, Edward discovers that Amos is secretly a werewolf but shows no ill-will towards his employer. Amos, upon returning to normal, reveals the woman is Sandra, and she attends Auburn University. Edward confesses his love to Sandra, but she declines his wedding proposal despite numerous romantic gestures. He then learns she is already engaged to Don Price, a fellow Ashton citizen. Don beats Edward in a fight, prompting Sandra to break off their engagement and marry Edward. Shortly after, Edward is conscripted into the army and sent to fight in the Korean War. He parachutes into the middle of a North Korean military show, steals important documents, and convinces Siamese twins Ping and Jing to help him go home in exchange for making them celebrities.
Upon returning home, Edward becomes a travelling salesman and crosses paths with Winslow, unwittingly helping him rob a failing bank, inspiring the poet to work on Wall Street. In the present, Will investigates the truth behind his father’s tales and travels to Spectre. He meets an older Jenny, who explains that Edward rescued the town from bankruptcy and rebuilt it with help from his friends from Calloway Circus. Will suggests that Jenny had an affair with his father, but she reveals while she loved Edward, he remained loyal to Sandra. Will returns home but learns Edward has had a stroke and stays with him at the hospital.
Edward wakes up but, unable to speak much, asks Will to narrate how his life ends. Though struggling, Will tells his father of their imagined daring escape from the hospital to the nearby lake, where everyone from Edward’s past is there to see him off. Will takes Edward into the river, where he transforms into the giant catfish and swims away. A satisfied Edward dies, knowing Will understands his love for storytelling. At the funeral, Will and Joséphine are surprised when all the people from Edward’s stories come to the service, though each one is a slightly less fantastical version than described. Will, finally understanding his father’s love for life, passes on Edward’s stories to his own son.

Question: What does Edward transform into during Will's story at the end?
Answer: A Catfish