text: whobob whatpants ? " what ever happened to spongebob ? " , promotionally known as " whobob whatpants ? " , is the 18th episode of the fifth season and the 98th overall episode of the american animated television series spongebob squarepants . the episode originally aired on nickelodeon in the united states on october 13 , 2008 . the series follows the adventures and endeavors of the title character and his various friends in the underwater city of bikini bottom . in this episode , spongebob feels neglected and ends up a nuisance when he tries to hang out with the other characters . they all call him " idiot boy " , so spongebob decides to pack up and leave bikini bottom . along the way , he accidentally bumps his head , making him lose his memory . spongebob wanders away into a new place called new kelp city and attempts to get a new job , unaware he is becoming a target for a criminal gang known as the bubble poppin ' boys , while patrick , sandy and a reluctant squidward try to find him . the episode was written by casey alexander , zeus cervas , and steven banks , and was directed by alan smart and tom yasumi . the episode features guest appearance by ray liotta as the voice of trevor , the episode 's villain . the episode 's premiere pulled an average of 7 . 7 million viewers , but was met with mixed to negative reviews . plot summary spongebob wakes up on a normal day as usual and attempts to hang out with patrick , squidward and sandy , however he ends up angering them each , causing them to call him " idiot boy " . spongebob heads to the krusty krab but ends up creating a mishap that results in getting two dollars fried and reduced to bits , with a furious mr. krabs kicking him out of the restaurant and like the others did , mr. krabs calls spongebob " idiot boy " . spongebob decides to leave bikini bottom and tells gary that he has a year 's supply of snail food to eat since spongebob will not be there to feed him . after leaving bikini bottom , he is frightened by bizarre people and as he runs in fear , spongebob falls off a cliff and bumps his head , knocking himself unconscious . back in bikini bottom , patrick and sandy enter spongebob 's house and sandy finds that gary 's food bowl has a note from spongebob , saying he has left so that he will not bother anyone ever again . after sandy reads it , she and patrick show remorse . meanwhile , spongebob wakes up with amnesia . he sees two fishes who have found his clothes and express interest in using them ; spongebob mentions that he cannot remember anything except hitting his head , so the fish tell him that his name is " " . however , they run away when they find out spongebob has a bottle of bubble soap . he wonders what the problem was and spots new kelp city . sandy and patrick arrive at the krusty krab where customers have gathered , angered about not getting their orders , sandy then shows the note from spongebob to mr. krabs . after he reads it , they all become upset about making him leave ( except for squidward who is happy about spongebob being gone ) . mr. krabs has the customers leave the restaurant , so that he and the other can decide on how to find spongebob . spongebob wanders around new kelp city and upon getting accused of pickpocketing by a civilian and noticing his hunger , decides he needs to get a job . each time he gets a job however , he uses bubble blowing , resulting in him getting fired . back in bikini bottom , after squidward ( who is to not see spongebob again ) destroys a device that sandy made to find spongebob , mr. krabs orders him to look for spongebob . squidward refuses at first but changes his mind when mr. krabs prompts him with his retirement gift : a fabergé egg . spongebob 's activity with blowing bubbles , brings up a confrontation with " the bubble poppin ' boys " , a greaser - like gang who have scared the city into never blowing bubbles because they keep being blinded by the bubbles whenever they pop . after they attack , spongebob uses his bubble blowing to trap the gang in a giant bubble that flies them out of town . he is rewarded by getting the position of mayor of new kelp city while the previous mayor resigns . sandy , patrick , and squidward arrive at a gas station and from reading a newspaper article , discover spongebob 's appointment as mayor of new kelp city . but when they go to new kelp city to retrieve him , spongebob cannot remember who they are . squidward hi - jinks spongebob 's limousine and gets away from the city with spongebob , patrick and sandy in tow and they return to the krusty krab . spongebob still does not recall the eatery and wants to return to new kelp city to resume his job as mayor . delighted that spongebob is leaving again , squidward requests for his jewel encrusted egg but slips and accidentally throws the egg onto spongebob 's head , which causes his memory to come back . but even so , spongebob still wants to return to new kelp city . he changes his mind after a breaking news report comes on , saying that the bubbles in new kelp city are blinding the citizens , and a thug threatens to do something to spongebob if he ever comes back . spongebob starts cooking krabby patties again , much to his friends ' delight . with a sigh of happiness , spongebob says that it looks like he will be back in bikini bottom . upon hearing this , squidward takes out his brain and drops it in a trash can . production " what ever happened to spongebob ? " , also known as " whobob whatpants ? " , was a special episode written by casey alexander , zeus cervas , and steven banks . it was directed by alan smart . alexander and cervas also functioned as storyboard directors . the episode was first announced by nickelodeon on september 24 , 2008 on a press release . according to the network , spongebob " wanders the ocean , a stranger in his own pants , " and finds himself in a rough part of new kelp city , where he faces off against the boys ' , liotta 's character . the episode originally aired in the united states on october 13 , 2008 . from october 3 , 2008 , turbonick featured a special playlist of content dedicated to the episode , including a sneak - peek of the special , themed episodes , short - form content , song clips , and an instant replay of the special following the television premiere . nick.com , in 2008 , presented a new game called " spongebob squarepants : whobob whatpants ? " to celebrate the episode 's television airing . the episode also features spongebob 's signature sea altered to " whobob whatpants ? " during the chorus answers in the title sequence . in addition to the regular cast , american emmy award winning actor ray liotta guest starred in the episode as the voice of trevor , the leader of new kelp city 's bubble poppin ' boys gang , and the main villain in the episode . on october 14 , 2008 , " what ever happened to spongebob ? " became available in the dvd compilation called spongebob 's whobob whatpants , along with six other episodes including " goo goo gas " , " the two faces of squidward " , " " , " banned in bikini bottom " , and " stanley s. squarepants " . reception " what ever happened to spongebob ? " was viewed by 7 . 7 million audiences . this ranked the program the number one most viewed entertainment show of the night , and the number two most viewed show in all categories after espn monday night football . despite the high ratings , the episode received mixed to negative reviews from critics . maddy said that the episode was " extremely fun and entertaining . " he added " i hadn 't watched spongebob in a while , but the laughs in this episode provided more laughs than i would get in an entire day . " maxie zeus of toon zone cited the episode as an example of the series ' decline . lesley aeschliman of yahoo ! voices wrote " i have to look at this special like the ' friend or foe ? ' special . while ' whobob whatpants ? ' works well as a regular story for spongebob squarepants , i 'm not entirely convinced that it deserved to be hyped up as a special . while this story had the potential to be ' special material , ' it just didn 't materialize in the final produced product . " roy hrab of dvd verdict said , " it makes me sad to think about how something so pleasurable has declined into something so tedious . " paul mavis of dvd talk said , " with a laugh - skimpy script , ' what ever happened to spongebob ? ' may be confirming a trend i noticed back with the last original spongebob toon to get its own disc release , pest of the west : spongebob shorts are starting to get tired . and ' what ever happened to spongebob ? ' is even less funny than ' pest of the west ' , " adding the episode was " not a good sign . "