Alligator

Never Smile At a Crocodile, but what happens when it smiles at you?

It's 36 feet long, weighs 2000 pounds, lives 50 feet below the city. Nobody knows it's down there except the people it eats.

Alligator is a 1981 horror/comedy film, directed by Lewis Teague and starring Robert Forster, with a screenplay by John Sayles, in which "Ramon", the eponymous beast, runs amok in the Chicago sewer system after feeding on covertly discarded growth hormone. The film is notable for being among the first of the slew of Jaws homages/rip-offs to be produced by the American movie industry. Unlike 99% of the horrors that have come lurching along in its wake, the humor is intentional, the human characters are sympathetic, and the flick is worth seeing.

Tropes used in Alligator include:

• Absurdly Spacious Sewer
• Children Are Innocent: Subverted more than once.
• Corrupt Corporate Executive
• Cowboy Cop: The hero's reputation, even though it's not exactly deserved.
• Da Chief: A more sympathetic and intelligent version than usual.
• Egomaniac Hunter: The ill-fated Col. Brock.
• Great White Hunter: Again, an overt parody in the form of Col. Brock.
• Hot Scientist
• Intrepid Reporter: Subverted, in that the guy is an obnoxious jerk, but genuinely goes looking for scoops, eventually taking crucial pictures of Ramon, even as he is devoured.
• Infant Immortality:
  • Averted when on a dare, a kid jumps off the diving board of his backyard swimming pool at night while the alligator is momentarily staying in it. He realizes at the last moment what is happening and tries to step back, but his friends push him in anyway because they didn't see it and think he chickened out.
  • However, it was played straight when a little girl toddler was in the back yard with her mother's wash. Mom hears the phone ring, goes in to answer it, and along comes the titular beast. Mom sees the monster leave the yard, screaming and crying as she looks for her child. Then the little girl lifts up the clothes basket she was hiding under!
• Karmic Death: Ramon kills the Corrupt Corporate Executive whose experiments inadvertently created him.
• Mad Bomber: This is literally the name of one character in the credits. Might called a case of "Chekov's Explosives"...
• Never Smile At a Crocodile
• Nigh Invulnerability: Ramon
• Nightmare Dreams: David has these from the first encounter with Ramon.
• Numbered Sequels: With Oddly-Named Sequel 2: Electric Boogaloo.
• Pet Baby Wild Animal: Subverted. Ramon gets unceremoniously flushed into the sewer while still tiny, and his former owner then makes every effort to help kill him.
• Reptiles Are Abhorrent
• Shout-Out: The graffiti in the sewers, the name of the sewer-worker Ramon kills.
• Suspiciously Stealthy Predator: Because it just wouldn't be a Jaws ripoff if the beast let anyone but the hero realize it was out there too soon, would it?
• Stock Footage: The sequel uses snippets of footage from the first film's alligator sequences in some scenes.
• Talking the Monster to Death: Literally if sarcastically suggested by the Hot Scientist, in reference to her motor-mouthed mother.
• The End - or Is It?: The film ends with another alligator getting flushed into the sewer.