Alligator is a 1980 American horror film, directed by Lewis Teague with a screenplay by John Sayles. It stars Robert Forster, Robin Riker, and Michael V. Gazzo. It also includes an appearance by actress Sue Lyon in her last screen role to date.
A teenage girl purchases a baby American alligator while on vacation with her family at a tourist trap in Florida. After the family returns home to Chicago, the alligator, named Ramn by the girl, is promptly flushed down the familys toilet by her surly, animalphobic father and ends up in the citys sewers.Twelve years later, the alligator survives by feeding on covertly discarded pet carcasses. These animals had been used as test subjects for an experimental growth formula intended to increase agricultural livestock meat production. However the project was abandoned due to the formulas side effect of massively increasing the animals metabolism, which caused it to have an insatiable appetite. During the years, the baby alligator accumulated concentrated amounts of this formula from feeding on these carcasses, causing it to mutate, growing into afoot 11m alligator, as well as having an almost impenetrable hide. ........
Source: Wikipedia