The joke in my part of the world used to be "a black cat in a coal cellar at midnight". That this is also a cat makes me think that the artist might be familiar with that idiom.
Mine was "darker than a black cat in a coal mine at night" but I think it's just easier for hicks with an accent to say. Far less racist than the other ways they would say "dark".
Haha yeah sorry... I spent to much time in some backwater places in the south and Midwest parts of America and heard it a whole lot.
Heard it used for other things too... But one use stood out above the rest in my memories.