lyricists like GZA and Ras Kass have been known to use real metaphors where the comparison of 2 separate things are drawn together as one
"yo Big L is a legend, he got crazy metaphors"
"Look inside my rap book at every text my man
and see that I got, more essays than a Mexican"
Big Daddy Kane
"that nigga kane knows how to flip a Metaphor (In Rap)"