SpongeBob SquarePants (1999)

S9E26 The Sewers of Bikini Bottom

After an unfortunate mishap involving Mr. Krabs' safe being flushed down the toilet, SpongeBob and Squidward find themselves on a quest through the sewers to retrieve it. Meanwhile, Mr. Krabs heads to the newly opened stadium, where he discovers some serious plumbing problems that need addressing.