In the beginning he was mostly a shapeless mass of black space. But despite the lack of body, he did own a belt. (He must have worn it somewhere. A waist of space?)
Anyway, from this belt dangled a pouch containing shiny twinkling crystals. In an effort to define himself, he took to sticking them all over his body — join-the-dots fashion.
And there he is to this day, his outline picked out in all the most important stars. If you know where to look.
The dog star Sirius was an afterthought, put there by the meddling COYOTE in a fit of cosmological hindrance. The BLACK-GOD wouldn’t let him touch the pouch but COYOTE snatched it anyway. He tasted the crystals inside, didn’t like the flavor and spat them into the face of the Black God, who snatched the pouch back.
But there was nothing left but dust, which he shook out, forming the Milky Way.