I couldn't figure out how to comment on his character page, so I'm putting this here. After comparing the original worm song to the 2003 worm song, my extremely vivid imagination came up with my own theory on the relationship between Spadge and Boggy:
When they were kids in school, Spadge and Boggy are playing soccer in gym class when Boggy accidentally hits Spadge in the face with the ball. He feels terrible and goes with Spadge to the nurse's office, but the two bond over the accident and quickly become inseparable, grow up together, and join the army together.
Now, in the original song, Spadge is Boggy's best friend. In the 2003 song, Clagnut "son of Spadge" is Boggy's nephew. So I figured when Boggy's father left for war, Boggy had an infant sister. I genuinely did not know Suzette was a thing (or maybe I had seen her somewhere but never thought of her as related to Boggy... Pretty sure that's it), so I named this sister Sissy D. Anyway, as they grow up, Spadge finds himself in love with her but, for a while, is afraid of what Boggy might think. When he finally gets the courage to tell him how he feels about Sissy, Boggy tells him that he's overheard Sissy talking to her friends about how much she likes Spadge.
With Boggy's permission, Spadge confesses his love to Sissy, the two start dating, and eventually get married and have Clagnut together. Boggy is more than happy to call Spadge his brother-in-law and they remain the best of friends right up to the events of the original song.
...... I'm going to stop there because the war stories in my extremely vivid imagination would probably fill an entire book. Boggy B fights in six wars, three of them alongside Clagnut. At one point, Clagnut is nearly killed when rescuing a child from a warzone while Boggy is almost killed rescuing the child's teddy bear.
...... I need to shut up now. XD