Trivia: The cuckoo bird was used at the beginning of the movie to point out what a parasitic bird does - secretly lays eggs in the nest of another bird species and leaves them for the different species to raise as their own. Another "brood parasite" that many people might be more familiar with is the Brown-headed cowbird. If all goes as intended, the different species, such as a Cardinal, will take care of the eggs until they hatch and continue feeding fledgings. Sometimes, "alien" eggs are evicted.
Trivia: Spoilers. In the end, Dr. Butler and his wife Stephanie are revealed to be the killers. They were actually the killers in the original script for the first film, but the ending was changed several times until the final version seen in theaters with Lori being the killer. The original idea was recycled into this film, since the dimension-hopping angle of the story allowed the presence of a new version of the killer.
Trivia: Stay for hilarious outtakes after the credits with Eryka Badhu giving psychic feedback.
Trivia: Arnold Schwarzenegger's "performance" in this movie "merited" a nomination in the 2021 Razzies (Raspberry Awards) for WORST supporting actor, but he lost [or would that be "won"?] to Rudy Giuliani! Arnold's nomination had some good company: Chevy Chase, Shia LaBeouf, and Bruce Willis. Bruce was nominated for THREE of his movies - Breach, Hard Kill, and Survive the Night.
Trivia: Marks the fourth "Ring/Ringu" film to be directed by original "Ringu" director Hideo Nakata. Nakata had previously directed the original Japanese film "Ringu" in 1998 and its sequel "Ringu 2" in 1999. He also directed the film "The Ring Two" in the American remake series. This will be the first Japanese "Ringu" film he has directed in 20 years.
Trivia: This film shares a lot of similarities with the 2007 film Superbad. In fact, Beanie Feldstein, who plays Molly, is the sister of Jonah Hill, who plays Seth in Superbad.
Trivia: When the screenwriter was pitching the film back in the 90's, reportedly at one meeting an executive suggested in all seriousness that Julia Roberts should play Harriet Tubman. When another person in the room mentioned that it wouldn't make any sense for the (very white) Roberts to play the role of Tubman, he responded "It was so long ago! Nobody would know the difference!"
Trivia: Seeing the "In God We Trust" sign on the classroom wall of a public school might lead some to question its Constitutionality, but it has been the National motto since the 1950s. Post-9/11, some states started REQUIRING the motto be posted in public places, including public schools beginning the 2019-20 academic year. (00:06:20)
Trivia: The Mermaid spit "ink" at Dr. Beyer in his car. This suggests a Mermaid is similar to an octopus, squid, or cuttlefish (which have "ink sacs" - though anal, not oral!) and is a type of mollusk, not fish. However, mollusks are invertebrates, and the Mermaid in the movie apparently had a spine/backbone. (01:13:28)
Trivia: After the police arrived, Hayley told Sarah, "It is not my fault my parents put a LoJack in my car." LoJack is a high-tech GPS system and theft recovery device that can pinpoint a car's exact location. LoJack ended sales in the U.S. in 2021 (will not accept any new orders but will continue to service existing connected vehicles). (00:41:50)
Trivia: Spoilers: Among the video-tapes seen next to the TV after the opening credits are "C.H.U.D." and "The Goonies." This is quite relevant to the plot, in which it is revealed that the doppelgangers come from beneath the ground in a series of tunnels that used to be run by the government. "C.H.U.D." is about mutant creatures that live underground and have began to rise up and attack, like the doppelgangers, and "Goonies" takes place largely in underground tunnels and caverns, much like the film's climax.
Trivia: The scene where Devon Sawa talks about Limp Bizkit was not scripted. He was doing some improv and did a whole bit about how much he likes the band as a joke and a nod to director Fred Durst, who is the lead singer of the band. Sawa and Durst didn't intend for the take to be used in the finished film. However, when it was picked up for distribution, the studio had the film slightly recut and decided to use the take, slightly embarrassing the two.
Trivia: The film features a cameo from Frank the pug, who appeared in the first two films, but was absent from "Men in Black 3." Oddly enough, despite only appearing in the film for a few seconds, Frank appears quite prominently on several posters and even on the DVD cover art for the film. (The same is true for the "worm guys," who also appear on posters and the DVD cover despite only having a brief cameo in the film).
Trivia: When Kim throws a henchman over the railings onto Professor Dementor, the henchman lets out a Wilhelm scream.
Trivia: The filmmakers had originally planned to shoot the film at Banff National Park, but the direction of the park did not like the fact that one of the bad guys was an Indigenous gang boss, and therefore the filming permit was revoked.
Trivia: The first "Critters" film to be rated R, as well as the first film in the series to not feature actors Don Keith Opper and Terrance Mann.