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.