The Humu (Coalsack) is the name of a dark patch in the milkyway, close the constellation of Crux (southern cross). It is so named, because it has the shape of a triggerfish, humu.
In the myth of the both Maʻafu, humu was a fresh water fish, caught by the two boys, and later together with a toloa and the twin themselves placed into the sky.
Even when not in the sky Humu and Toloa are still good friends as in the following trite:
Humu and Toloa plant their plantain plant plant then overgrown with bush. A Fiji dog runs along being welcomed with a shot missed in the leg but hit in the liver It then let out its loud cry.