A Mudshark Melody is simply a cheap rap/r&b song that is played on the radio and attracts many jersey tugging white women. For some reason, by creating cheap songs and hitting particular off-notes, coupled with the common 4/4 beat, white women get all hot and bothered when they hear these songs.
The word mudshark refers to women who are on the hunt for some dark chocolate, no matter what dark chocolate it is, they want some.
Melody meaning a succession of tones or notes. In this case, cheap rappers make it easy to remember for mentally impaired audiences (aka mudsharks).
Example 1: The casual response.
Boy 1: Dammmmnnn, did you just hear that new Chris Brown song? Girls love him even though he hits his girlfriend.
Boy 2: It must be one of those Mudshark Melodies.
Example 2: Confronting the Mudshark.
Mudshark: That new Soulja Boy/Trey Songz duo is hot.
Boy 1: Why is that? Sounds like another Mudshark Melody.
Mudshark: They are the best rappers alive! Their songs are soooo deep and intimate.
Boy 1: How about you go wash that mud off and go listen to some real music.
Mudshark: You don't know shit!
Boy 1: How about you go tug on some more jerseys and show up at some more football parties?
Mudshark: I don't swim in the mud all the time.
Boy 1: Of course you do, you mud tossen ho! Now turn off that radio before I chum dis water and catch your shark ass myself.