Looking on the internet deeply has found these results:

upon the beast's back is the most popular phrase on the web.

sat upon the back of the beast 12 results on the web	upon the beast's back 110,300 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
And lo, the beast looked upon the face of beauty... A monument of Rome built upon the backs of slaves. Wouldn't want our Littlefriend here to wind upon the back of a milk carton, now wouldwe? And lo, the beast looked upon the face of beauty... And He that sat upon the throne said, The back of the Cézanne says Rothschild. My ancestors sat upon the throne of a great country when yours still crawled on their hands and knees, feeding on insects. And He that sat upon the throne said,	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

sat upon the back of the beast

12 results on the web

upon the beast's back

110,300 results on the web

More popular!

And lo, the beast looked upon the face of beauty...
A monument of Rome built upon the backs of slaves.
Wouldn't want our Littlefriend here to wind upon the back of a milk carton, now wouldwe?
And lo, the beast looked upon the face of beauty...
And He that sat upon the throne said,
The back of the Cézanne says Rothschild.
My ancestors sat upon the throne of a great country when yours still crawled on their hands and knees, feeding on insects.
And He that sat upon the throne said,

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.