Alligator, the 1980 giant beast in the sewers b-movie, was directed by Lewis Teague (Cujo, The Jewel of the Nile) and had its screenplay written by John Sayles, who was also behind the Roger Corman-produced hit Piranha (1978). The story sees a baby alligator bought by a young girl in Florida, and subsequently named Ramón, flushed down the sewers in Los Angeles by her animal-phobic father. The film then jumps to twelve years later and the reptile has grown to the size of a bus after eating the corpses of dead pets that have been injected with a secret growth formula and dumped into the sewers. After human body parts begin showing up with alarming regularity the world-weary detective David Madison (genre stalwart Robert Forster) is sent into the sewers to investigate what’s behind the murders, along with reptile expert Marisa Kendall (Robin Riker – as pictured on this poster), the girl that originally flushed Ramón into the sewers.
The film features an infamous scene where Ramón escapes from the sewers and rampages through a high-society wedding murdering anyone who crosses his path. This scene can be viewed on YouTube.
This is one of two Japanese posters for the film that I’m aware of, and I’ve called this the ‘black style’.
The original trailer is on YouTube.