A convicted killer attempted to murder a fellow inmate by slitting his throat in an East Ayrshire jail.
James O'Rourke, 49, attacked Thomas Peacock with a "pointed piece of metal" while they were both exercising in HMP Kilmarnock.
He pled guilty to attempted murder at the High Court in Glasgow and had nine years added to his sentence.
O'Rourke has been behind bars since 1992 after murdering a man in Airdrie, North Lanarkshire.
Much of the time on his sentence has been added for various violent attacks across different prisons.
'That's what you get'
CCTV captured O'Rourke's latest attack on Peacock - who is also a convicted murderer.
Prosecutor Liam Ewing QC said the two had been exercising when O'Rourke grabbed Peacock after approaching him from behind then slit his throat.
He added: "O'Rourke was heard to state: 'That's what you get'."
The court was also told O'Rourke ran off while Peacock went downstairs clutching his neck.
O'Rourke was stopped by guards and admitted having a "broken comb" - but handed over what was described as a "piece of pointed metal".
On later being told Peacock appeared to have survived the attack, O'Rourke replied: "Pity".
O'Rourke's extra jail time
- 1997: Six years after a prison officer and nurse were held hostage at HMP Glenochil
- 2002: Eight years for assault and abduction
- 2004: Four years for an attack
- 2005: Eight years for stabbing a prison escort and senior jail official at HMP Kilmarnock
Peacock is serving a life sentence for helping to kick a man to death in Barrhead, East Renfrewshire, in 2005.
He is known as the pizza box murderer because he and an accomplice put the box over their victim's face so they would avoid getting blood on their clothes.
After being attacked by O'Rourke, he needed surgery for a 20cm wound and has been left permanently scarred.
Peacock claimed to have no idea who attacked him or why he was attacked.
Lady Scott told O'Rourke the sentence would have been 12 years, but for the guilty plea.