He was an eccentric and loveable Dubliner who regularly 'shot' people from his favourite position on the back of the 50A bus.
And now the city is to permanently preserve the weapon of choice of the man known simply as 'Bang Bang'.
For a whole generation of Dubliners, the key brings about fond reminders of Thomas 'Bang Bang' Dudley, a much-adored character and fan of Westerns who rode at the back of buses from the 1940s to the 1970s.
With his trusty '45' -- the rusty key -- Mr Dudley would playfully 'shoot' passers-by along with his trademark "bang bang" shout.
Dr Mary Clarke, from the Dublin City Library and Archive on Pearse Street, said yesterday: "His favourite trick was to hop on the old 50A bus -- they had a platform at the back -- and he would go 'bang bang' to all the citizens.
"There were really hard times in the 1940s and 1950s and he provided this harmless amusement."
Along with pictures of Bang Bang, the key will now be on display at the library.
Born in 1906, Mr Dudley was sent to an orphanage when his mother could not look after him following the death of his father.
Mr Dudley, who lived in a small house on Mill Street in the Liberties, became well known in the city with his playful antics.
Dr Clark said. "He was a grown-up child and this was just a game he was playing."
As he got older and succumbed to blindness, Mr Dudley was taken into the care of the Rosminian Fathers in Drumcondra. He died on January 11, 1981.