One of the thugs who attacked student Paul Gibbs in a Rothwell Park was filmed rapping about his love of violence, drug-taking and robbery weeks before the horrific attack.
Quinn Colley, 18, appears in the home-made clip with three other teenagers in which he threatens to stamp on his victm's brains.
Goth who lost ear in attack tells of operation hope: Click here for interview.
Colley carried out the attack on Mr Gibbs and the other goths while on
bail for another appalling act of violence just a month earlier.
* Click here to sign up to free news and sport email alerts from Rothwell Today.
In the amateurish youtube footage, Colley, who is introduced as MC QC, also takes pleasure in describing blowing a rival's head off, hanging someone, carrying out a stabbing and a baseball attack.
In the clip, called Jog Thugz, he also refers to a violent attack while high on drugs.
* Click here for latest news in Rothwell, Oulton & Woodlesford.
Leeds Crown Court heard how, shortly before the incident, Colley had told friends he had lost his phone.
He then said to them: "We'll go and rob the Moshers, we'll get money and iPods. We will have about 12 phones."
Colley also offered to get the biggest member of the group (Mr Gibbs) so that the others would "back off".
Another attack took place in Rothwell country park, on July 26 last year. David Croll needed surgery after his jaw was fractured when Colley knocked him to the floor, and punched him repeatedly in the face before headbutting him in the nose.
Colley admitted causing grievous bodily harm with intent, in addition to the attack on Mr Gibbs which took place just over four weeks later on August 28.
Colley, who was handed an indeterminate sentence for the public's protection, must serve a minimum of two years and 210 days but will only be freed when the parole board are satisfied he no longer presents a danger to the public.