What it actually is is covers of the entirety of Ram, Paul McCartney's second solo record from 1971, that he produced and then sat on for six years until he got bored or whatever and decided to create a fake person to release it as
But he didn't just release a record of covers of his own record--he placed these ads and gave Percy a social scene (and a... ram's head) and then didn't admit it was him for another 15 years
Ah, the cover art is by Hipgnosis, which was responsible for some of the greatest album covers of the '70s including virtually the entire Pink Floyd catalog.
Thrillington is a 1977 lounge instrumental record by Mr Thrillington,a socialite who only ever existed in classified ads about his comings and goings.