The Bubble Bowl is a large bowl shaped building which only appears in "Band Geeks."
Squidward has to perform in front of a live human audience, in the episode "Band Geeks." He has been challenged by his nemesis, Squilliam, and is nervous because his band has not shown to be very good during practice. One night before the big concert, a riot starts up among the band members and Squidward storms off disappointed.
SpongeBob comes to the rescue with an inspirational speech and they practice throughout the night. The next day the band is ready and Squidward is nervous. They end up singing "Sweet Victory" amazingly, causing Squilliam to faint and be taken to the hospital.