Addendum 9/3/2021: You can read an academic style write-up about the grootslang at A Book of Creatures.
So I learned of another legendary creature, the grootslang from Dahomey. Its name literally translates to "great snake" and it basically behaves like the traditional treasure hoarding dragon. Some things never change, even across continents. Several explorers claimed sightings of it over the centuries.
Of course, the internet misinformation machine had to screw it up. It's commonly depicted as an elephant/snake hybrid in modern art, even though I couldn't find any primary sources describing it as such. There's also a story circulating about its origins as the ancestor of snakes and elephants, which I could not find in any primary source either; in fact, I suspect this story originates from the Pathfinder RPG directly. Some sources claim the grootslang has a red gem or diamond in its forehead, or even that it has such gems for eyes and/or bewitching powers over onlookers. These are similar to some other stories of dragons, particularly the French vouivre I blogged about before.
There's a bunch of other misinformation floating around too that I can't source either. I suspect the artistic depiction of an elephant/snake hybrid originated as a misunderstanding of it being "elephant-sized." Somewhere along the line an artist or writer misunderstood this as "elephant-shaped" and we got our modern elephant-headed snake. Again, I wonder if Pathfinder originated this too, as I can't find any older art on Deviantart.
Funnily enough, Final Fantasy depicts it as a generic giant snake.
Basically, it's a very typical example of the terrifying treasure-guarding dragons. One detail that is often omitted is that grootslang is the Afrikaans name for the creature and may be more description than actual name. Other accounts call it "Kiman."
Sober accounts tell of a great snake called Kiman cruising the remote canyons between Augrabies and the Richtersveld, preying on stock. The colourful ones claim the snake has a diamond embedded in its forehead, that it entices young girls into the water and knocks men down with its breath. (p258. Dicey, William. Borderline. South Africa, Kwela Books, 2004.)
At Groot Derm I first learnt of the Groot Slang, the Big Snake of the Orange River. The Hottentots believed this snake had a diamond in its head which scintillated in the moonlight, and was brilliantly visible for long distances during the day. (p127. SWA Annual: SWA Jaarboek. SWA Jahrbuch. Namibia, South West Africa Publications, Limited, 1973.)
Enticing girls? Yeah, that's obviously omitted by a lot of the elephant hybrid stories. As you might have noticed by the "colourful" appellation, stories of the great snake are subject to embellishment. Learning more about the actual accounts is very difficult because they're in books that aren't freely available on Google Books. Darn copyright laws.
So Kiman is a very typical dragon all things considered: giant snake, lives in water, hoards treasure, hunts livestock, seduces women, terrifies men, beautiful gem in its forehead, etc.