- Development Hell: The end of the book teased a sequel called The Adventures of Ook and Gluk Jr.: Kung-Fu Cavekids in Outer Space, which was supposed to be "Coming Soon-ish!!!" This may, however, have been a Lampshade Hanging of the earlier two instances of Development Hell for the Captain Underpants series. Given that the original book was pulled from publication in 2021, it's safe to assume that no sequels will ever be written.
- Old Shame: In the wake of an increase in hate crimes against Asian-Americans and Pacific Islanders in 2021, Pilkey expressed regret towards The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future for having harmful racial stereotypes and passively racist imagery against Asians and had the book pulled from print.
Trivia / The Adventures of Ook and Gluk: Kung-Fu Cavemen from the Future