The Bikini Bottom Triangle is an island that appears in the episode "Welcome to the Bikini Bottom Triangle."
The mermaids are the first people to settle here. The island contains many items taken by the mermaids via singing to activate a giant vacuum, which opens a rift in the sky while doing so. When they sing their song backwards, the items are returned to their owner. The place from a far looks like a dump.
Role in episode
The Bikini Bottom Triangle serves as a major plot point of the episode.
One night in Bikini Bottom, a mysterious fog appears and the voices of mermaids are heard singing. That morning, SpongeBob realizes his alarm clock, Gary's shell, Squidward's clarinet, Patrick's cuff links, and Mr. Krabs are missing. While investigating, SpongeBob, Squidward, and Patrick are sucked into the triangle. They find Mr. Krabs, who tells them that he loves all the piles of "resellable stuff." He realizes that Pearl is left alone at the Krusty Krab with all his money, but she gets transported to the triangle too.
Pearl and Squidward relax, Mr. Krabs looks for change, and SpongeBob and Patrick look for the mermaids. The mermaid quintet only knows how to "surround themselves with cool new stuff" whenever they feel like. They call SpongeBob's dilemma "TNOP" (totally not our problem). SpongeBob then quickly says upon return, "Unfortunately, I was unable to get the information from the aauugh," and being noticeably tired, he simply collapses. Mr. Krabs realizes SpongeBob desperately needs a Krabby Patty. He finds one close by and feeds it to SpongeBob. He then wonders who makes that Krabby Patty. Suspecting that Plankton might have stolen the formula, Mr. Krabs intends on getting back to the Krusty Krab as soon as possible.
The whole group goes to the mermaids, Pearl wants to go to the mall, and the mermaids want to go too. SpongeBob has an idea and hypothesizes that if the mermaids sing their song backwards, it will also reverse the effects of the vacuum, and so the mermaids begin to sing backwards. They get sucked back to Bikini Bottom.