Well, I knew Gaibon would have been a big stretch off those guys.
But anyway, as much as it might disappoint the people who believed Slogra was some kind of dinosaur, the truth of the matter is he was just some demon thought up by an artist painting his rendition of a very, very popular scene from the history of Christianity.
Then when I looked into it a bit, when you consider Slogra's original name was Beligan, (or Berrigan in some transliterations). Beli- may have come from Belial, the -g- may have just been a conjunction, and -an may have come from Anthony. Then again, the duo's name may have also just been based on jazz musicians.