- Development Hell: An eighth book called Naughty Night Crawlers from Neptune was scheduled to succeed after Uranium Unicorns from Uranus, but unfortunately, it never got off the ground for years due to a Schedule Slip before finally being completed after the series reboot.
- Meaningful Rename: The series underwent one because readers noticed that calling the robot "giant" was incorrect due to the setting being a Mouse World and requested Pilkey change the title to reflect this.
- Schedule Slip: After Uranium Unicorns from Uranus was published because Dav Pilkey was taking care of his terminally ill father (who eventually passed). Captain Underpants was also put on hiatus for the same reason.
Trivia / Ricky Ricotta's Mighty Robot