Trivia: The family of late author Roald Dahl who wrote the novel The Witches gave director Robert Zemeckis permission to do a remake on the condition that the ending of the movie follow the ending of the book, where the boy remains a mouse.
Trivia: This is the first time since 1988 where Frank Welker does not provide the voice for Fred Jones.
Trivia: The scientist Sarah has the video call with is a real theoretical physicist called Clifford Johnson, who's served as a consultant for films and TV shows including Agent Carter, Thor: Ragnarok, Avengers: Infinity War, and Avengers: Endgame.
Trivia: Dave Franco was a co-writer and (first-time) director of this movie. Dave's real-life wife, Alison Brie, starred as "Michelle." Alison (38) is about 2.5 years older than Dave (35).
Trivia: There are several subtle references to the 2018 film "Searching" in this movie. Most notably, the stock-photo model Hannah from "Searching" is briefly seen in this film in a thumbnail image for a YouTube video. Director Aneesh Chaganty has stated that this was intentional, and that "Searching," "Run" and by extension, "Missing" (the semi-sequel to "Searching") are all set within the same cinematic universe.