Mourning Glory is a song by American rock band Ween released from their third studio album Pure Guava in 1992.
According to the Tumblr user ebilflindas, the song was originally used in the ending credits of the first SpongeBob SquarePants movie in 2004, but due to its failure with test audiences, it was ultimately replaced from the final version with the more popular "Ocean Man", a song released from the same band's sixth studio album The Mollusk in 1997.
This short video of the workprint of the film featuring the same song was partially found and posted on Tumblr by the same user in 2016. An edited version was made and uploaded on YouTube by Narwhix, who saw this information and became interested in doing his own edited extension to the short video.
To be added