- Not Betty (debut)
- Ted (debut)
- SpongeBob SquarePants
- Gary the Snail
- Snail-Po mascot (debut)
- Nat Peterson (last name revealed)
- Purple fish
- Norma Rechid
- Patrick Star
- Diner Chef (debut)
- Squidward Tentacles
- Debbie Rechid
- Daydream Archie
- Daydream Dave
- Daydream Fred
- Daydream Mable-Monica
- Daydream Vera Fishbowl (cameo)
- Bank robber (debut)
- Eugene Krabs
- Old Man Jenkins (cameo)
- Two guys who threw SpongeBob in the dumpster (mentioned)
- Stingray 5000 band member (debut)
- Clams (written on CD)
- Betty (mentioned)
SpongeBob is at a diner on a dark and weary morning, while rain is pouring down outside. A patron is solving a crossword puzzle, and realizes that he has lost his pen. A waitress says he can borrow hers, and does. SpongeBob says he once lost something: his identity.
He recounts the events of last Monday. In the flashback, He wakes up, and throws his blanket into the air, and says "Good morning, world, and all who inhabit it!" The blanket falls on him, and SpongeBob, being unable to see, falls off of his bed and his alarm clock falls on top of his head. He falls down the stairs and the alarm propels him into the window. He feeds Gary, and comments that he has been feeding Gary snail food for years and doesn't even know what it tastes like. He tastes it, is revolted, and his screaming of disgust is sensed at the headquarters of the company that makes the snail food. He looks at the clock and realizes that he is late for work, and quickly gets changed and skips to work. While he is skipping to work, Patrick greets SpongeBob.
Later, as SpongeBob serves food to a customer, the customer tells him that he should wear a name tag so that she can thank him properly. He indicates that he is indeed wearing a name tag, but then realizes that his name tag is missing. He panics, hyperventilates, and eventually faints.
When he wakes up, he asks Squidward what happened. Squidward tells him that he fainted because he lost his name tag, but assures him that his name tag is not that important, and SpongeBob hyperventilates once again. However, just as he says this, Mr. Krabs comes out of his office and informs them that there is a uniform inspection in one hour and anyone who fails has to wear a very stinky boot all day. Squidward suggests to SpongeBob that he should retrace his steps.SpongeBob repeats everything he did that morning several times, including his "horrific incident of terror" with the alarm clock and eating the snail food. SpongeBob repeats this many times since Patrick continuously fails to say "Hi" to him. As an example, Patrick accidentally says "Hi, SpongeBoob" and laughs afterwards. Still, SpongeBob fails to find his name tag. Patrick asks him if he did anything else on his way to work, and SpongeBob says that he said hello to Old Man Jenkins, put an apple on Mr. Krabs' desk, and was thrown into a dumpster by two thugs. Patrick suggests looking in the dumpster, and they go to search there.
During the search, SpongeBob gives Patrick two hints but he is still confused. SpongeBob does a double take of Jack Benny while wondering, but panics that he has one minute left. Patrick finds SpongeBob's name tag on the back of his shirt, and when he alerts him to this and SpongeBob turns around, it seems to disappear and Patrick cannot remember where it was. SpongeBob gets irritated after he does this twice and soon tells Patrick, but when Patrick says "At least I don't wear my shirt backwards!," SpongeBob realizes that he had his name tag all along, and his shirt was just on backwards. At the uniform inspection, however, Mr. Krabs smells SpongeBob and is disgusted by the stench of the dumpster, and seemingly suspends him from working at the Krusty Krab.
SpongeBob finishes telling his story, and thanks the waitress for listening, calling her "Betty." She says that her name is not Betty, and that she is just borrowing someone else's uniform while hers is getting cleaned. When SpongeBob learns this, he ends the episode doing a Jack Benny double-take, similarly to an earlier scene.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Marching to Honolulu - Kapono Beamer [title card]
‣ Eastside Story (a) - Trevor Duncan [opening]
‣ On the Beach - Kapono Beamer ["Good morning, world, and all who inhabit it."]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [at the Krusty Krab]
‣ ? - Nicolas Carr ["Thanks... uh..."]
‣ On Fire - Gregor F. Narholz [SpongeBob notices his name tag is missing]
‣ Pua Paoakalani (b) - Kapono Beamer, Queen Lili'uokalani [SpongeBob cries]
‣ Against the Law (c) - Wilfred William Burns [bank robbery]
‣ On Fire - Gregor F. Narholz [SpongeBob panics]
‣ The Rake Hornpipe - Robert Alexander White ["Attention, all employees!"]
‣ On Fire - Gregor F. Narholz [SpongeBob panics again]
‣ Harp Ding - Nicolas Carr ["Squidward, you're a genius!"]
‣ Hawaiian Happiness - Jon Jelmer [SpongeBob going back home]
‣ On Fire - Gregor F. Narholz [Patrick panics]
‣ On the Beach - Kapono Beamer [SpongeBob retracing his steps]
‣ Vergnügungspark - Gerhard Trede [Patrick flubbing his lines]
‣ Ulkereien - Gerhard Trede [SpongeBob remembering what else he did that morning]
‣ Hawaiian Link (b) - Richard Myhill [SpongeBob and Patrick standing in front of the dumpster]
‣ Witty Fellow - Gerhard Trede [looking for SpongeBob's name tag in the dumpster]
‣ Steel Sting - Jeremy Wakefield ["Could I have another hint?"]
‣ Dramatic Cue (b) - Ronald Hanmer ["One minute?"]
‣ Vibe Sting - Nicolas Carr [Patrick sees SpongeBob's name tag]
‣ SpongeBob Closing Theme - Steve Belfer, Nicolas Carr ["Uh... I can't remember."]
‣ Marching to Honolulu - Kapono Beamer [SpongeBob's shirt is on backwards]
‣ Up She Rises - Sam Spence [uniform inspection]
‣ Eastside Story (a) - Trevor Duncan [SpongeBob finishes his story]
‣ Steel Sting - Jeremy Wakefield [Hawaiian sting at the end]
- "Missing Identity" was ranked #75 during the Best Day Ever event on November 9–10, 2006.
- When this episode first aired on Nickelodeon, it came second, while "Plankton's Army" aired first. This was due to "Plankton's Army" being heavily advertised as the episode where Plankton finally gets the Krabby Patty secret formula.
- Running gags:
- SpongeBob wakes up, and saying "Good morning, world, and all who inhabit it." The blanket blinds him, making him fall off the bed, and then his foghorn clock falls onto him. He walks out of his room and trips down the stairs. His foghorn alarm sounds again, blowing him into the window. He slides toward Gary, says his "horrific incident of terror" is over, feeds Gary while singing about his meal, and decides to taste Gary's Snail-Po food, screaming "Bleah!" afterwards.
- Patrick bloops his line and SpongeBob has to start all over.
- A character realizes SpongeBob's name tag is missing and starts hyperventilating.
- When Patrick bloops his line saying, "SpongeBoob," he then says "Sorry people," as if a crew was filming the whole thing, subsequently breaking the fourth wall.
- The fourth wall is broken again when the waitress says, "Well, ya managed to kill eleven minutes," referencing the length of a normal SpongeBob episode.
- The bank robber in SpongeBob's imagination somehow has a different name tag than what SpongeBob actually has.
- The title card is the same as "Reef Blower," but it is green instead.
- The name tag is somehow based on the one from "Help Wanted." Both have only SpongeBob's first name and an anchor in the middle of the background.
- SpongeBob yells "Pourquoi?" to Squidward at one point in this episode. "Pourquoi" means "why" in French.
- It is revealed that Nat's last name is "Peterson."
- This is the first time someone calls SpongeBob "SpongeBoob." The second time is in The SpongeBob SquarePants Movie and the third time is in "SquidBob TentaclePants."
- This is the first episode where the main plot is told via a long flashback sequence. This flow goes the same for the five episode vacation miniseries: "A SquarePants Family Vacation," "Patrick's Staycation," "Walking the Plankton," "Mooncation," and "Mr. Krabs Takes a Vacation."
- The snail in the Snail-Po logo in this episode has a shell identical to the one of Lary the Snail. Additionally, they look very similar, though, the former does not have a unibrow.
- In "SpongeBob You're Fired," SpongeBob is able to make the Snail-Po recipe. It is possible that he remembers the taste from this episode.
- This is the second episode where SpongeBob tastes snail food. The first was in "I Was a Teenage Gary." The fact that he has stated to have never eaten snail food previously in this episode indicates that it took place before "I Was a Teenage Gary."
- Old Man Jenkins makes a cameo appearance in this episode with his jalopy car, just like in "Sailor Mouth."
- When SpongeBob retraces his steps, he does not do the clothes changing, which is why he had to do it more times other than Patrick not saying his lines.
- In the Tagalog version, the line "SpongeBoob" is changed to "SpongePoop."
- In the October 23, 2015 airing, this episode was paired with "Graveyard Shift."
- At the beginning of the episode, there is a crossword. Four of the five things written are "Squid," "Chum," "Wet," "Seaweed," and "coral."
- This episode aired in Germany on September 24, 2003, before it aired in the USA.
- This episode is the first time Zeus Cervas was mentioned in the title card opening credits.
- In two separate instances, when Patrick asks for a third clue and the waitress said that the name tag on her borrowed uniform wasn't hers, SpongeBob places his left arm on his right elbow with his right hand on his chin, like Jack Benny did on his 1950s TV show.
- The scene where the Snail-Po executive feels a disturbance after SpongeBob tastes a can of Snail-Po is a parody of the scene in Star Wars Episode IV: A New Hope where Obi-Wan Kenobi feels a disturbance after Alderaan is destroyed.
- SpongeBob makes a reference to the game Twenty Questions in the dumpster scene.
- The band Patrick finds in the dumpster, "Stingray 5000" is a parody of the Powerman 5000.
- Snail-Po is a reference to Alpo dog food.
- The cash register is missing when Squidward brags about being a "genius."
- When SpongeBob turns around, showing his collar and name tag, the amount of filth on his shirt changes between scenes.
- Whenever SpongeBob turns around, his collar is not shown. This is done purposely to not ruin the story.
- At the Krusty Krab, during the second collapse SpongeBob suffers after passing out, there is no animation of Squidward crossing his arms.
- When SpongeBob is trying to retrace his steps with Patrick, Squidward's house is not shown between SpongeBob's and Patrick's house.
- When SpongeBob is retracing his steps and it shows all of Conch Street and Patrick, there is a window on the top left corner of SpongeBob's house, where there never is.
- In the scenes before SpongeBob and Patrick go in the dumpster, SpongeBob is shown from behind, but his name tag is not seen. Later in the dump, Patrick sees the name tag on SpongeBob's back.
- In the Hebrew translation, when SpongeBob tries to spell Patrick the word "name-tag," it sounds wrong since in Hebrew it is: "tagit shem" - "tag of" and "name," and he said: "name" and "tag of."
- Mr. Krabs said whoever didn't pass would have to wear a stinky boot all day. However, all he did was kick SpongeBob out of the Krusty Krab. This may have been because he thought SpongeBob smelled really bad even without the boot.
- During the splitscreen of SpongeBob's attempt to retrace his steps, when he says "Bleh!" the lower right box has him slamming into the window though this happened earlier. Also, he doesn't say "Bleh!" when hitting the window, but when he eats Snail-Po.