Novelization
The film was novelized in 1977, in paperback under the pseudonym of "Carl Dreadstone", as part of a short-lived series of books based on the classic Universal horror films. The book was introduced by Ramsey Campbell, but was written by Walter Harris. The novel offers a completely different Gill-man, who in this version of the story is gigantic, almost as big as the Rita herself, weighing in at 30 tons. It is both coldblooded and warmblooded, is a hermaphrodite, and also possesses a long whip-like tail. The gigantic creature is dubbed "AA", for "Advanced Amphibian", by the expedition team members. After slaying most of the team members, destroying a Sikorsky helicopter, and kidnapping Kay more than once, the creature is killed by the crew of a US Navy torpedo boat.
The novel also differs greatly with respect to the human characters. Only David Reed and Kay Lawrence remain the same. Mark Williams is a German named "Bruno Gebhardt", and dies not as a result from drowning but by the monster falling on him. Lucas is named "Jose Goncalves Fonseca de Souza" and is a mostly sympathetic character until his suggestion of throwing the wounded and unconscious Reed to the monster makes an enraged Gebhardt/Williams throw him to the beast instead. Dr. Thompson and Dr. Maia both die grisly deaths, whereas in the movie they survive; Maia is eaten by the monster, and Thompson is impaled on a long tree branch flung at him by the creature like a spear (in an apparent nod to a deleted scene from Revenge of the Creature wherein the Gill-man killed a guard in this fashion).
Read more about this topic: Creature From The Black Lagoon