SpongeBob SquarePants chronicles the adventures and endeavors of the title character and his various friends in the fictional underwater city of Bikini Bottom.
Many of the ideas for the show originated in an unpublished, educational comic book titled The Intertidal Zone, which Hillenburg created in the mid-1980s.
He began developing SpongeBob SquarePants into a television series in 1996 upon the cancellation of Rocko's Modern Life, which Hillenburg directed.
The first credited guest stars were McHale's Navy actors Ernest Borgnine and Tim Conway, who appeared in "Mermaid Man and Barnacle Boy (I)", the show's sixth episode.
Aside from the aforementioned actors, actress Marion Ross has a recurring role as Grandma SquarePants, SpongeBob's grandmother.
As of May 4, 2016[update], there have been 78 guest stars on the show,[A] with this figure rising to 84 if The SpongeBob SquarePants Movie and its sequels are included.
Guest stars have appeared on SpongeBob SquarePants since its first season, in addition to the main cast, consisting of Tom Kenny, Bill Fagerbakke, Rodger Bumpass, Clancy Brown, Mr. Lawrence, Jill Talley, Carolyn Lawrence, Mary Jo Catlett and Lori Alan.
Series creator Stephen Hillenburg in point of fact eschewed appearances by celebrities on the show, stating in an early interview, "Honestly, I deliberately avoided that.
"[5] According to Tom Kenny, main character SpongeBob's voice actor, "One of the things networks always try to push is getting celebrities."
"[6] The first guest stars to appear on the show were actors Ernest Borgnine and Tim Conway,[7] reuniting for their first joint TV project in 33 years since the 1960s sitcom McHale's Navy.
[18] Borgnine's former McHale's Navy co-star Conway has made over 15 guest appearances as Barnacle Boy, Mermaid Man's sidekick.
[24] Writer Steven Banks said, "It's not just stunt casting to get publicity," and that the reasoning is "[we] do want to meet them [...]"[25] A number of guest stars have accepted to appear on the show after being persuaded by their children who are SpongeBob SquarePants fans.
"[4] SpongeBob SquarePants has a "dream list" of celebrities that the crew would like to appear on the show, which includes actors Michael Caine and Jerry Lewis.