If one is going to do a Jaws ripoff, this is how it should be done — with tongue planted firmly in cheek, and none of the dour mood that pervades a film like Orca.
Directed by Lewis Teague from a screenplay by the immortal John Sayles, Alligator tells the tale of a mutated alligator that lives in the sewers of Chicago and likes to munch on any hapless person who wanders by.
Following a popular urban legend of the day, a young girl receives a baby alligator as a souvenir from a trip to an alligator farm in Florida and, after the family returns home to Chicago, it is unceremoniously flushed down the toilet, landing unharmed, and probably quite annoyed, in the city sewers. Fast-forward to many years later, and the baby gator is now all grown up, and then some.
How did it get that way?
Well, a local pharmaceutical concern has been working to develop growth hormones that it hopes to use on livestock, creating heifers of enormous size to satisfy world hunger, and rake in the profits. They’ve been going through test animals — specifically, dogs — quicker than they would like, so have to source the animals from shady pet store owner Luke Gutchel (Sydney Lassick) to make up the difference. There are laws and regulations regarding test animals, though, so they also make Gutchel dispose of the animals once they are dead and full of growth hormone. Of course, Gutchel has been tossing them in the sewers where, unbeknownst to him or anyone else, the alligator has been gobbling them up and packing on the pounds.
It’s at this point that viewers will notice that while this movie takes place in Chicago, it was very much filmed in Los Angeles, as the LA River and the city’s system of storm drains are featured players. Also, the cop cars and uniforms in this film resemble LAPD’s 
gear more than Chicago’s. At least I didn’t spot any palm trees (I’m looking at you, Children of the Corn III), although the mountains surrounding Los Angeles make an anachoric appearance.
It doesn’t make much sense to have the film look so Los Angeles but take place in Chicago. Maybe Teague wanted to take advantage of star Robert Forster’s excellent Chicago accent, but that accent is itself an anachorism, as his character is from St. Louis. Anyway, enough with the fifty-cent words.
Forster plays Detective David Madison, the cop assigned to investigate all the random body parts the gator is leaving behind. After he spots the beast while scouting the sewers, he is met with much skepticism — the only other people who would believe him having been turned into alligator poop.
As if things aren’t bad enough for Madison, he has gotten on the bad side of the mayor, who has a close relationship with the villainous Slade (Dean Jagger), owner of the company that is carrying out the hormone experiments.
Eventually concrete evidence of the gator’s presence does surface, and for his efforts, Madison is kicked off the force. The duties of hunting the gator have now passed to self-styled ‘Colonel’ Brock (recently deceased Henry Silva), a character who ratchets up the silly to epic proportions.
Silva was very much in on the joke, his key scene being a TV interview he gives in which he imitates the distress and mating calls of an alligator, all with a straight face. Every moment he’s on screen is a treasure.
A climactic scene, where the alligator crashes a garden party at Slade’s lavish mansion, is the icing on the cake.
All of this leads to denouement where Madison, and love interest/herpetologist Dr. Marisa Kendall (Robin Riker), are forced to take care of business.
This is a very satisfying monster flick. It hits familiar tropes one after the other, but it’s done so well that the lack of originality is no offense. The idea of a gigantic killer alligator is strong, and the execution, despite a limited budget, is believable. The effects team delivered something just convincing enough, while Teague and cinematographer Joseph Mangine were smart enough to keep the creature mostly in shadow. Top to bottom, the performances are good, with the exception of Michael V. Gazzo as Madison’s boss. He flubs some lines here and there, and also operates under the burden of having played Frankie Pentangeli. Perhaps he wasn’t right for the role.
Other than that, the only thing I would have liked to have seen was a little more gore, but I can’t ding the film for what we viewers got. Alligator is a welcome addition to the October Horrorshow.