The great Overdog
That heavenly beast
With a star in one eye
Gives a leap in the east.
He dances upright
All the way to the west
And never once drops
On his forefeet to rest.
I'm a poor underdog,
But to-night I will bark
With the great Overdog
The constellation looks like a dog standing upright. Metaphorically, the speaker is admiring that the Overdog is always enjoying life and never lets the bumps in the road slow him down.
Canis Major