"Campfire Song Song" is a song that SpongeBob sings in the episode "The Camping Episode." Patrick was singing as well, but he could not catch up because SpongeBob was singing far too fast, so he instead resorted to playing the drums near the end.
SpongeBob: [spoken] I call this one, the Campfire Song Song. [SpongeBob playing the ukulele]
Let's gather 'round the campfire and sing our campfire song.
Our C-A-M-P-F-I-R-E S-O-N-G song.
And if you don't think that we can sing it faster then you're wrong
And if you don't think that we can sing it faster then you're wrong,
But it'll help if you just sing along.
Patrick: [in the background, struggling to keep up]Sing another song!
SpongeBob: C-A-M-P-F-I-R-E S-O-N-G song, Patrick!
Patrick: Song! C-A-M-P-F-I-R-E...
[Squidward keeps silent and just stares at them]
It'll help, it'll help!
If you just sing along!
[Fireworks, SpongeBob smashes the ukulele, Patrick slams a drum on SpongeBob]
On the year of its release in Australia, Nickelodeon Australia made a competition for all kids around Australia, which was whoever could sing the song fastest (by taking a video of themselves singing it and posting it for the competition) would win a multitude of SpongeBob merchandise.
This song is the most known song in the series, and has been featured in many films, and other TV series. One example is in the Family Guy episode "Road to Rupert," in which Peter Griffin watches the episode's scene were SpongeBob and Patrick sing the song. The song was written by Dan Povenmire who was a director on that Family Guy episode.
Because of this, he was able to gain the rights to his own song.