It's worth noting that Madagascar was settled fairly recently in human memory. Some Austronesians had arrived at some point between 350 BC and AD 550, but it wasn't really settled with vigor until the Bantu latecomers around ~1000 AD.
In fact, much of Africa was settled and colonized by Bantu tribes that arrived not much earlier than the Europeans, and in some places (such as in modern South Africa), after them. The Bantu played the key role in displacing the 'aboriginal' African populations, such as the 'bushmen' and 'pygmies'. Far from primitive, the Bantu were an explosive, dynamic society with advanced agricultural and military technology. In many ways, they fared much better than the Indians or the Chinese during the 19th century, in terms of dealing with the Europeans.
Shaka Zulu was a Bantu descendant who managed to create a highly centralized and organized society that would have impressed a Prussian junker.
So that is essentially the story of Madagascar. You're not going to find anything equivalent to say, the aboriginal population of Australia, which settled there up to ~50,000 years ago. In terms of independent creation mythology, anyways.
it may be worth x-posting this question to our sister sub, /r/AskAnthropology
In the most common Malagasy creation narrative, there are two creators. The first is Andriananahary, the Lord Who Creates, also known as Zanahary. Zanahary created the universe, after which, Andriantompo, the Lord Who Owns, also known as Ratovantany, sprung out of the earth. This was quite unexpected so Zanahary went to investigate. He found Ratovantany shaping clay figurines of people and animals. Seeing Ratovantany's disappointment when these creations didn't come to life, Zanahary use his own power to animate them. This cooperation became a short-lived friendship, but in time, Zanahary and Ratovantany had an argument over what to do their creation. Zanahary wanted to return to the heavens and take them with him since he had breathed life into him. Ratovantany argued that there would be nothing to have accepted that life had he not made the figurines to begin with. Eventually they came to a compromise. These creations would remain on the earth for a time, then Zanahary would take their animating force back to the heavens with him, and Ratovantany would take their corporeal vessel back down into the earth.