According to Sean Astin, he was allowed to keep the treasure map used in the film. Several years later his mother Patty Duke discovered it, thought it was just a crinkled piece of paper, and threw it in the trash.
When rocks are falling from the cave ceiling, Jonathan Ke Quan (Data) screams "Holy S-H-I-T!" He said he spelled the expletive because his mother made him promise not to use any bad language in the movie.
Cyndi Lauper co-wrote the theme song "Goonies R Good Enough", and shot a music video that features a cameo by the film's executive producer Steven Spielberg. The 12-minute video basically tells the movie's story as a musical. Cyndi Lauper plays Cyndi (a new Goonie recruit), The Bangles play pirates, and André the Giant plays Sloth.
Though they were divorcing at the time, Patty Duke claims that she and John Astin held hands and sobbed through the entire film when they saw it for the first time. Patty is Sean Astin's Mother and John is his step-father.
One Eyed Willie's ship, The Inferno, was 105 feet long and took 2-1/2 months to construct. It was modeled after Errol Flynn's ship in The Sea Hawk (1940). The sails required more than than 7,000 square feet of material, the largest measured 30ft by 60ft. Some of the ship's rigging was recycled from the Pirates of the Caribbean ship at Disneyland, which was being renovated at the time.
John Matuszak's make-up took 5 hours to complete. One of the eyes (which was out of place on the face) was mechanically operated off-screen by remote control. Someone would count down, and Matuszak would blink his other eye in synchronization. The cast was told not to get him wet in scenes outside of the pirate ship. Unfortunately, he got wet, delaying filming for an entire day.
According to director Richard Donner in an interview with "The Directors", producer Steven Spielberg instructed the cast members to act cold and distant toward Donner on the last week of filming which puzzled him. Shortly after filming wrapped, Donner went to his beach house in Hawaii, ran into a frenzied neighbor who took up his entire day. When he arrived home, the entire cast was there with Donner to celebrate with a cookout. Spielberg flew them over to Hawaii on the promise that they not speak a word of the surprise to Donner, which prompted them to act the way they were on the last week of filming.
Mikey mentions Michael Jackson going over to Chunk's house in one scene. In real life, Corey Feldman (who played Mouth) was close friends with the singer and the two later became estranged. Feldman attended Michael Jackson's memorial service after his death in June 2009.
The name "Rube G" can be seen painted on the contraption that opens the yard gate for Chunk near the beginning of the movie. This is in reference to Rube Goldberg, the Pulitzer Prize winning cartoonist who drew whimsical machines that achieved simple results in difficult ways.
The Goonies Oath that was cut out goes as follows: "I will never betray my goon dock friends / We will stick together until the whole world ends / Through heaven and hell, and nuclear war / Good pals like us, will stick like tar / In the city, or the country, or the forest, or the boonies / I am proudly declared a fellow Goony."
In the original version of this film, the woman hired by Mikey's mother is a Hispanic named Rosalita (Lupe Ontiveros), and Mouth helps Mrs. Walsh by translating her commands into Spanish. In the Spanish version of this film, Rosalita becomes an Italian woman named Rossanna. The Italian used by the Spanish dubber is much better than the Spanish used by Corey Feldman.
The late Corey Haim auditioned for the role of Mouth, but the role was given to Corey Feldman instead. At the time the two Coreys hadn't met, but they were later cast together in The Lost Boys (1987) and became best friends, starring in 6 more movies together. In License to Drive (1988), Feldman auditioned for the lead role of Les Anderson, but lost it to Haim.
On the DVD commentary, Jeff Cohen (Chunk) claims that the confession of puking off the theater balcony is not based on anything in real life. This is incorrect. The basis for the theater story was a real-life prank pulled by Executive Producer Steven Spielberg while growing up in Phoenix, AZ.
Production Designer J. Michael Riva said in a National Public Radio interview that before shooting the first scenes with the prop map, he thought that it looked good but not old enough, so in his hotel room, he aged it with coffee and (when he couldn't find paint) his own blood.
In the storybook of the film, One-Eyed Willy's back-story is told by Francis Fratelli, when The Fratelli's take the doubloon from Chunk. One-Eyed Willy, whose real name is William B. Pordobel, was a court jester, before becoming an ingenious pirate, when he was banished from five Spanish courts, for his practical jokes and formed a band of pirates, whom marauded hundreds of the king's ships and accumulated a treasure worth millions. But, Willy's ship "Inferno" was attacked by three of the King's ships and Willy steered his ship into a hidden underground cavern and was sealed within by the canon fire from the British. Willy and his men had spent a couple of years trying to repair the ship and had built underground caves with weird booby traps to protect the treasure and one of Willy's men escaped to tell Willy's story, which became a legend.
In the storybook of the film, there was a scene, that was not in the film. Mikey, Mouth, Brand, Data, Andi and Stef discover a room with a dangling skeleton in a pirate's costume. The Goonies had to tickle the skeleton's elbow, which would point to one of three tunnels, where they must go. Stef tickles the skeleton's elbow and it points to the middle cave and The Goonies continue the search for One-Eyed Willy's treasure.
The original poster art (not used on the video tape box) featured the cast dangling from the feet of another with the top one hanging on a rock. Some of the newspaper ads featured slightly different artwork with the characters drawn in a different order from top to bottom.
The MAD Magazines Mikey looks through at his house are #208 July 1979, #124 January 1969 and #254 December 1984 (this issue can be seen in the Stop-N-Snack Scene eventually cut from the film. MAD Magazine made a Parody out of this movie in late 1985.
When Chunk is hiding from the Fratellis in the refrigerator with the dead body, he sneezes loudly. As Mama Fratelli exits the room she unwittingly says "Gesundheit!", the German word for "Health" used as a response to a sneeze.
The soundtrack includes "8 Arms To Hold You" by "The Goon Squad". It was removed from the film when the octopus scene was cut. The filmmakers were convinced the song could be a hit, so it was pressed as a 12" dance single. It sold miserably due to lack of promotion. It has become one of the rarest, most valuable Goonie-related items.
Some of the crew members played extras in the film. One cameraman played Mouth's father. Another played the dead man in the freezer. And an assistant director plays one of the cops on the AV scooters on the beach at the end.