Alligator is a standard monster movie the latter half in particular references Them! (1954). However, the screenplay, from no less than a young John Sayles, makes deft and amusing variations on cliches Sayles did similar things with his script for Piranha (1978) like Henry Silvas parody on the Great White Hunter. There is a darkly amusing sense of humour at play like the little boy who runs back and forward with kitchen knives as he tries to convince his mother, engaged in a phone conversation, of the nature of the menace, and a wonderfully nasty sequence where kids force another to walk the plank in a swimming pool. Fun.
Director Lewis Teague rose to notice here and would go on to several other associations with the genre with the Stephen King adaptations Cujo (1983) and Cats Eye (1985), the sf film Wedlock/Deadlock (1991) and the tv movie The Triangle (2001), and other mainstream hits such as The Jewel of the Nile (1985) and Navy SEALS (1988). The script for Alligator comes from John Sayles who wrote a number of B movies like this, Battle Beyond the Stars (1980) and The Howling (1980), before making his name as a prominent indie writer/director with films like The Brother from Another Planet (1984), Matewan (1987), Passion Fish (1992), The Secret of Roan Inish (1994), Lone Star (1996) and Men with Guns (1997), Limbo (1999), Sunshine State (2002), Case de los Babys (2003), Silver City (2004) and Honeydripper (2007).
The lame Alligator II: The Mutation (1991) was a sequel.
Film online in several parts beginning here:-