Bikini Bottom 3D is the main setting in SpongeBob SquarePants. The city proper has a population of about 2,000,000, but the entire metro area (including Jellyfish Fields) has a population of over 4,000,000. The city consists of various businesses, including restaurants, stores, and manufacturers. The city has a stable economy, a balanced education system, questionable health care (as seen in "The Lost Mattress") and labor laws, a structured government, and a firm law enforcement system (though this is questionable as well, as some as both Plankton and Mr. Krabs have broken many laws and have only been punished on a few occasions). There are even stadiums, amusement parks, and other recreational facilities. Bikini Bottom was first mentioned in the episode, "Plankton!", but first appeared in the episode, "Help Wanted." Bikini Bottom is also home to the main characters of the cartoon.
In M.U.G.E.N, Bikini Bottom was made by Xedarts and EXShadow. Xed's take takes place on "Conch Street", as it's known in the cartoon, more commonly associated with being the street Spongebob Squarepants, Squidward Tentacles, and Patrick Star live on. EXShadow's version is taken from the Unreal Tournament 2004 map of the same name.