An HMP Bullingdon inmate - who is known by his nickname 'psycho' - inscribed the name of a prison officer on to a makeshift blade.
The chilling discovery was the fourth in a series of similar offences Mohammed Islam was later charged with.
The 20-year-old prisoner had already admitted four counts of having inside a weapon an offensive weapon.
Outlining the case at Oxford Crown Court today prosecutor Jonathan Veasey-Pugh said all the offences took place while at the prison near Bicester.
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Islam is currently serving a a three-year jail term for intimidating witnesses and perverting the course of justice.
The court heard that while at the prison he was caught on four separate occasions with makeshift weapons.
He was found to have prison 'shanks' as well as a tin of coconut oil wrapped in a sock.
The last weapon discovered had the word 'psycho' inscribed on it, an apparent reference to himself, as well as the name of a prison officer.
In mitigation James Partridge said that his client had not used any violence in connection with having the weapons.
He added that an incorrect rumour had been started at the prison claiming Islam was in prison for child sex offences and he had fallen out with fellow inmates.
Sentencing, Judge Ian Pringle QC said the fact Islam had inscribed the name of a prison officer was 'rather more intimidating and rather more serious' than only having the items.
Islam was jailed for six months, which will run consecutive to his existing jail term and he must pay a victim surcharge.
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