BlackJack SquarePants Father is most likely unknown, as he has never been mentioned in any of the episodes of the show. It is possible that he could be anyone, as there are many fathers in the show’s fictional world of Nickelodeon. It is also possible that he could be a figment of SpongeBob’s imagination, or that he actually does not exist at all. However, given that BlackJack SquarePants has a strong resemblance to SpongeBob and that the character is mentioned in at least one episode, it is more likely that BlackJack SquarePants Father is SpongeBob himself.
This would make sense given that BlackJack SquarePants often takes on characteristics of SpongeBob, such as being stupid and overconfident. Additionally, it has been hinted that SpongeBob may have a secret identity, and this would certainly fit into that idea.
