Jayo Felony - "Trued Up" (lost music video; 2001)
In 2001, San Diego based gangsta rapper Jayo Felony released a diss track titled "Trued Up" targeted at Jay Z that called him out as a phony. This ended up essentially going nowhere, as Jayo hadn't made an album since. A music video was made for the song however.
Around the late 90s, Jayo Felony ended his contract with Def Jam Records and went underground, after achieving modest success with his 1994 album Take a Ride and then with Watcha Gonna Do in 1998. Afterwards, he released two underground albums in 1999 (Underground) and 2001 (Crip Hop).
During this time, a beef started between Jay Z and Jayo Felony for unknown reasons. It's been speculated that it may have been due to Jayo being released from the label (label politics). According to an MTV News article, Jayo took offense to Jay Z's perceived insulting of the West Coast hip hop scene and his arrogance. Jay Z also apparently attempted to get the song from getting released.
Allegedly, a music video was released and aired on MTV or BET once. It's unknown why it was essentially banned, but it's been speculated Def Jam Records got it off the air.
The music video has not been released in any way since its supposed TV airing and, while a user on the Siccness.net forums supposedly uploaded the video on YouTube in 2011, it was eventually taken down.