Question: In what year did this pilot episode air of this American animated television series, whose title character held the same name as the show and also included the character Mrs. Puff?

Context paragraphs:
Mrs. Puff: Mrs. Puff is a fictional character in the American animated television series "SpongeBob SquarePants" and both films based on the franchise.  She is voiced by actress Mary Jo Catlett and debuted in the season one episode "Boating School" on August 7, 1999.  Mrs. Puff was created and designed by marine biologist and animator Stephen Hillenburg.  He developed the character in response to a request from Nickelodeon that the show star a schoolteacher.  Hillenburg did not want to write SpongeBob as a school-age child, so Mrs. Puff was introduced as his driving instructor rather than a classroom educator.

The Itchy &amp; Scratchy &amp; Poochie Show: "The Itchy & Scratchy & Poochie Show" is the fourteenth episode in the eighth season of the American animated television series "The Simpsons".  It originally aired on the Fox network in the United States on February 9, 1997.  In the episode, "The Itchy & Scratchy Show" attempts to regain viewers by introducing a new character named Poochie, whose voice is provided by Homer.  The episode is largely self-referential and satirizes the world of television production, fans of "The Simpsons", and the series itself.  It was written by David X. Cohen and directed by Steven Dean Moore.  Alex Rocco is a credited guest voice as Roger Meyers, Jr. for the third and final time (having previously provided the character's voice in "Itchy & Scratchy & Marge" and "The Day the Violence Died"); Phil Hartman also guest stars as Troy McClure.  Poochie would become a minor recurring character and Comic Book Guy's catchphrase, "Worst episode ever", is introduced in this episode.  With "The Itchy & Scratchy & Poochie Show", the show's 167th episode, "The Simpsons" surpassed "The Flintstones" in the number of episodes produced for a prime-time animated series.

Mary Jo Catlett: Mary Jo Catlett (born September 2, 1938) is an American actress.  She is notable for her role as housekeeper Pearl Gallagher on the television sitcom "Diff'rent Strokes", and currently for her role as Mrs. Puff in "SpongeBob SquarePants", which she has held since the show's debut.

SpongeBob SquarePants (character): SpongeBob SquarePants is the titular character and protagonist of the American animated television series of the same name.  He is voiced by actor and comedian Tom Kenny and first appeared on television in the series' pilot episode on May 1, 1999.

Jake the Dog: Jake the Dog is a fictional character and one of the main cast in the American animated television series "Adventure Time" created by Pendleton Ward.  He is voiced by John DiMaggio.  The character made his debut in the original pilot.  Jake is Finn's best friend and adoptive brother.  He is a shape-shifting dog who is in his 30s in "magical dog years".  He was conceived by Joshua and an extra-dimensional creature and as a result, Jake can stretch, shrink, or mold any part of his body to any shape and almost any size, ranging from becoming gigantic to becoming incredibly small.  He acts as a confidant and mentor to his energetic brother, though has a tendency to give somewhat questionable advice.  Jake has a laid-back attitude in most situations, but loves adventure and will eagerly fight when he needs to.  His powers help Finn considerably in combat and transportation, but are also sometimes used as nothing more than jovial forms of expression.  Jake is in a relationship with Lady Rainicorn voiced by Niki Yang; they have five children together as seen in "Jake the Dad".  He met Lady in the pilot episode and is quite skilled at playing the viola, which houses a worm called Shelby.

Patrick Star: Patrick Star is a fictional character in the American animated television series "SpongeBob SquarePants".  He is voiced by actor Bill Fagerbakke, who also voices numerous other characters on the show.  Created and designed by marine biologist and cartoonist Stephen Hillenburg, the series creator, Patrick first appeared on television in the show's pilot episode "Help Wanted" on May 1, 1999.

Puff and the Incredible Mr. Nobody: Puff and the Incredible Mr. Nobody is a 30-minute animated television film loosely based on the song "Puff, the Magic Dragon" by Leonard Lipton and Peter Yarrow.  The title character was voiced by Burgess Meredith, and the film also featured the voice of David Mendenhall.  The special first aired May 17, 1982 on CBS.  This was the last "Puff the Magic Dragon" special.

Swamp Thing (1991 TV series): Swamp Thing is an American animated television series based on the Vertigo/DC Comics superhero character Swamp Thing.  The series is short-lived, with the pilot episode airing on October 31, 1990 followed by four additional episodes airing weekly from April 20 to May 11, 1991.  It aired on YTV from 1991 to 1993 in Canada.  Produced by DIC Entertainment, the series corresponded with Kenner's Swamp Thing action figure collection released in 1990.  Despite the animated series' brief run, various merchandise was also produced in 1991 resulting in the only significant marketing platform ever created for the character.

List of SpongeBob SquarePants guest stars: In addition to the show's regular cast of voice actors, guest stars have been featured on "SpongeBob SquarePants", an American animated television series created by marine biologist and animator Stephen Hillenburg for Nickelodeon.  "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 pilot episode first aired on Nickelodeon in the United States on May 1, 1999.  The show's ninth season premiered in 2012, and episodes of "SpongeBob SquarePants" have aired.  A feature-length film adaptation of the show, "The SpongeBob SquarePants Movie", was released in 2004; in 2015, a sequel, "", was released.

Television pilot: A television pilot (also known as a pilot or a pilot episode and sometimes marketed as a tele-movie) is a standalone episode of a television series that is used to sell the show to a television network.  At the time of its creation, the pilot is meant to be the testing ground to gauge whether a series will be successful, and is therefore a test episode of an intended television series.  It is an early step in the development of a television series, much like pilot studies serve as precursors to the start of larger activity.  In the case of a successful television series, the pilot is commonly the very first episode that is aired of the particular series under its own name.  A "back door pilot", is an episode of an existing successful series, that features future tie-in characters of an up-and-coming television series or film.  The purpose of the "back door pilot" is to introduce the characters to an audience before the creators decide on whether they want to pursue a spin-off series with those characters or not.

Supporting paragraphs: Mrs. Puff SpongeBob SquarePants (character)
Answer: May 1, 1999