Trying to find this Jay-Z diss song

I heard part of this song about 3 years ago on XM Radio, but don't know what it is. Rap song where they would play a couple of lines of a Jay-Z song, and then they would play the original song where he stole the lyrics from. Huge slam on Jay-Z calling him a punk for being unoriginal. Anyone know the name of the song and who it is by? I'd like to get it. Thanks!