It is a black bus with red flames on the top, behind, left and right. It has 3 windows on each side and there is a yellow fade between the windows.
The interior looks more realistic than the exterior. The interior is a gray room where in order to start the bus, you must sing. There is an robot in there that greets who comes inside the bus.
It first appeared in "Atlantis SquarePantis." In this appearance, it is summoned when Squidward connects the two halves of the Atlantean Amulet. One of the halves was in the museum and the other half was found in a cave by SpongeBob and Patrick prior to the connecting. Mr. Krabs and Sandy were also in anticipation of Squidward connecting the two pieces. The five enter the bus and are greeted by an Atlantian Bus Robot. The robot tells them that they lacked fuel, so they take the bus to a gas station. Mr. Krabs tries to put a fuel hose into the bus, but there is no gas tank. The robot tells them that the bus is powered by song. Sometime between the bus's summoning and the gas station scene, Plankton enters the bus, unnoticed, and enters the glove department. After the six find out that there is no fuel, there is a musical number in which each character, except Patrick tells of what they want from Atlantis. SpongeBob wants to see the world's oldest bubble. Mr. Krabs wants to have the money. Sandy wants to use the science. Squidward wants to see the art. Plankton wants to use the weapons. Patrick does not know what he wants, which makes the bus fall. Fortunately, they are close enough to Atlantis to make a crash landing there. They end up ruining part of Atlantis's topiary garden. It appears later, when Plankton escapes through the ventilation system and leaves the tail pipe. It does not appear until the end of the TV movie. After popping the oldest living bubble, running away from guards, having a run in with Plankton who now has a tank, finding out the tank shoots ice cream, having Plankton get upset, and Plankton replacing the Oldest Living Bubble, SpongeBob, Patrick, Mr. Krabs, Sandy, and Squidward leave Atlantis. There is one more musical number and a shot of Bikini Bottom at night appears and the bus becomes so small that it cannot be shown on screen.
Its second appearance is in SpongeBob's Atlantis SquarePantis. It first makes an appearance at the end of the first level, "Tanklantis Plankpantis!" In the cutscene for "Music Magical Journey!", it is summoned when Squidward connects the two halves of the Atlantean Amulet. One of the halves was in the museum and one half was found in a cave by SpongeBob and Patrick in a prior level. Mr. Krabs and Sandy were also in anticipation of Squidward connecting the two pieces. The five enter the bus. At some point, Plankton enters the bus, unnoticed, and enters the glove department. The five are greeted by an Atlantian Bus Robot. There is then a level in which SpongeBob, Sandy, Patrick, Squidward, and Plankton have to sing to gain fuel. In the cutscene for "Bus Building Bonanza!", the fuel runs out and they land in the garden. There is then an entire level where they fix the bus by collecting tool kits. In this level, it is reveled that there is more than one Atlantian bus. At the end of the level, they end up in the main part of Atlantis. It appears in the background of the first area of the next level, "Tour Trouble!". It is later appears in "Armory Antics!". Plankton escapes through the ventilation. It then briefly appears in the next area of the level. It then appears in the cutscene for "Super Tank Showdown!"/"Operation: Trash Dash!". Like in its first appearance, Plankton is chosen to replaced the Oldest Living Bubble. SpongeBob, Patrick, Mr. Krabs, Sandy, and Squidward get on the bus to leave. The Bus leaves. However, it appears floating around in "Operation: Trash Dash!". It also appears in the menu for the levels, "Music Magical Journey!" and "Bus Building Bonanza!".
It is later mentioned in "SpongeBob's Director's Commentary." SpongeBob mentions in a few times in his commentary for the "Music Magical Journey!" The most prominent thing that SpongeBob mentions is that after the production, SpongeBob and Patrick took the bus to Rock Bottom for some weekend trips. He mostly talks about it in his commentary for "Bus Building Bonanza!". He mentions that for most of the level, Sandy was driving. For the stunt driving, Patrick took over. Squidward wanted to drive, but ended up driving over a cliff. Mr. Krabs spent the entire scene crying under a bus seat, singing old sea shanties to himself.