Stephen Hillenburg, the creator of the show is a marine biologist, and presented his idea for the show to Nickelodeon in a bizarre way: He brought in a fish tank into the board room and explained what was living inside. He then placed a cartoon drawing of SpongeBob into the tank and said "This is SpongeBob, the star of your new show."
Stephen Hillenburg, the creator, stopped making new episodes in 2002 to work on the feature length film, The SpongeBob SquarePants Movie (2004). Because of this Nickelodeon had eight unaired episodes which they air at the rate of two or three a year.
Frequently, a French accented-voice comes onto to note a passage of time. This is an homage to Jacques-Yves Cousteau, who was a leading influence on creator Stephen Hillenburg and his interest in marine biology.
SpikeTV approached Stephen Hillenburg to do an "Adult" version of the show for their adult animation block. The show was to be similar in concept to Ren & Stimpy 'Adult Party Cartoon' (2003), Hillenburg refused to do it and Nick refused to sell the rights to SpikeTV.
Over the years, many fans of the show have asked Tom Kenny to lend SpongeBob's voice to their voice-mail and answering machines. In an interview, he joked that these custom messages might be more common than the factory-default voice.
The first episode aired (Bubble Stand/Ripped Pants) was, in fact, the second episode made. The pilot episode was "Help Wanted/Reef Blower/Tea at the Treedome" in which Spongebob gets his job at the Krusty Krab and meets his friend Sandy.
While Stephen Hillenburg was a director for Rocko's Modern Life (1993), he showed the show's writer 'Martin Olson' a comic book called "The Intertidal Zone" that Hillenburg drew in college. Olson loved it and suggested that Stephen rewrite it as an undersea cartoon series, which became SpongeBob SquarePants.
The seven main character's character traits appear to be based on the seven deadly sins. SpongeBob is based on lust which is the sin of having sexual desires with someone. Patrick is based on sloth, which is the sin of laziness and lack of motivation. Squidward is based on wrath, the sin of excessive hate and wrath. Mr. Krabs is based on greed, the sin of taking more and give little of something or nothing. Gary is based on gluttony, the sin of excessive eating. Sandy is based on pride, the sin of telling about how great you are. And Plankton is based on envy, the sin of wanting something that someone has.
In Korea Sponge Bob is referred to as "Square Square Sponge" or, quite often, "Square Square Sponge Song" (in the title song they needed four words to match the music and most children refer to him the second way).
In "Nature Pants", when spongebob leaves to start his new "nature" life. Sandy says "I'll give him a week." Squidward replies "I'll give him 11 minutes." This is referencing to the fact that each episode is approximately 11 and a half minutes, meaning Squidward won the bet.
In a 2015 interview, Tom Kenny (voice of SpongeBob) said that while recording the episode "Sailor Mouth", an episode in which SpongeBob learns a bad word, the voice actors were given clearance to actually swear during recording since it would be censored out. Whether or not an uncensored version of this episode exists is unknown.
The voice actors for Mermaid Man (Ernest Borgnine) & Barnacle Boy (Tim Conway) also played the main characters on the '60's TV show "McHale's Navy". Borgnine played Lt. Commander Quinton McHale and Conway played McHale's 2nd in command Ensign Charles Parker.
The signal flags hanging on the front of The Krusty Krab do not spell a word. In fact, the third signal flag (from left to right as you face the front door) does not exist in international nautical code. The first, second, fourth and fifth are R, I, U, and K respectively, although the U is only "right-side-up" if you read the flags from right-to-left. Inside Mr. Krab's office is _, I, R, and M. The _ has no letter associated with the flag
In the episode Mermaid Man Begins, it is revealed that the first names of Mermaid Man and Barnacle Boy are Ernie and Tim, which are the names of the voice actors. Ernest Borgnine (Mermaid Man) and Tim Conway (Barnacle Boy).
A so called "banned" episode titled "Squidward's Suicide" was posted on YouTube that depicts Squidward committing suicide. The episode allegedly depicts scenes of "violence and gore", as well as quick flashes of dead children and other disturbing imagery. A story that provides background for the video states that the episode was created in 2005 and was viewed by a select test screening at Nickelodeon. Show writer Casey Alexander debunked the legend, saying that the episode was a "100% hoax" and was not ever made by the show's staff.
The trivia items below may give away important plot points.
Every time a license is seen, SpongeBob says something about a mustache (Except for when he got his Milkshake license, where he said, "if only it were this easy to get my boating license!" And laughs).