The Goonies confirmed that it existed in the same universe as Gremlins based on an exchange between the Sheriff and Chunk. Gremlins memorably introduced the world to the mogwai and the reptilian creatures they could turn into. Both movies from the mid-'80s have gone on to become beloved cult classics.
Gremlins premiered in June of 1984 and was directed by Joe Dante. The horror comedy film notably took place during the Christmas season so many consider it a holiday movie. Gremlins followed a young man named Billy after he was given a mogwai for Christmas. In order to take care of the mogwai, Gizmo, Billy was asked to follow three rules: do not expose to bright lights or sunlight which will kill it, do not let it come in contact with water, and most importantly, never feed it after midnight. After the water was spilled on Gizmo, five other mogwais spawned from his back. The mogwais then turned into cocoons after they were fed past midnight. They then hatched into little reptilian monsters that wreaked havoc across the town.
A year after Gremlins made its debut, The Goonies was released. The comedy became an instant hit since it was appropriate for viewers of all ages. It centered on a rag-tag group of kids who embarked on a thrilling adventure. At one point during The Goonies, Chunk found himself left behind and stuck at the Fratellis hideout with Sloth. He managed to call the police and warned the Sheriff about the whereabouts of the crime family. Apparently, Chunk enjoyed pranking the police. The Sheriff responded to his request by recalling a time he called about "little creatures that multiply when you pour water on them." The "little creatures" line was a direct reference to Gremlins which confirmed their existence in The Goonies universe.
The Gremlins nod could be accredited to Steven Spielberg and Chris Columbus' involvement to both movies. Spielberg served as an executive producer on both films whereas Columbus wrote the screenplays. Even though no mogwais made an appearance during the hunt for One-Eyed Willy's treasure, it was a fun little nod connecting both movies. It's not uncommon for films to use clever Easter eggs connecting Spielberg movies, but this is a much more direct link.
The phone call with Chunk wasn't the only connection between the two movies. Corey Feldman, who played Clark "Mouth" Devereaux in The Goonies, also portrayed Pete Fountaine in Gremlins. Pete was the one that accidentally spilled water on Gizmo, setting off the events that unleashed the menacing creatures around town. Unlike The Goonies, Gremlins was given a sequel but there's still hope for the futures of both franchises. Both films have been in discussion for new installments. Gremlins will be the focus of an animated series, Gremlins: Secrets of the Mogwai, for the upcoming WarnerMedia streaming service, HBO Max.