When I saw the "best rap line" blog it made me think of this. My personal favorite is "A Fistfull of Teeth" by GWAR from their 2004 album "War Party":

              But one day my mood changed, and I melted your brain

                           A fistful of teeth is all that remained

                             I murdered you, and ate your soul

                           The bleakest black, the deepest hole

                                     I scream out your name

                                Or at least what I think you were called

                                   Fate's finger gives me the blame

                               If you saw my tears I know you'd be appalled

                                            A fistfull of teeth

                           I eat our child as I'm thinking of you

                You weren't here to feed me, so I ate our baby, I wish we'd had two  :)

                        So feel free to put your own favorite verse.