Swan Song

Meaning
A final gesture or performance, given before dying or retirement.

Origin
This term derived from the legend that, while they are mute during the rest of their lives, swans sing beautifully and mournfully just before they die. This isn't actually the case - swans, even the inaccurately named Mute Swans, have a variety of vocal sounds and they don't sing before they die. The legend was known to be false as early as the days of ancient Rome, when Pliny the Elder refuted it in Natural History, AD 77:

If people ever did believe in the 'singing before death' story, few would now claim to do so. 'Swan-song' is now used figuratively and most commonly to refer to celebrated performers embarking on 'farewell tours' or 'final performances'. Those ironic quote marks were never more appropriate than in the case of Nellie Melba, whose swan song consisted of an eight year long string of 'final concerts' between 1920 and 1928. This led to the popular Australian phrase - 'more farewells than Nellie Melba'.

Lets go out with guns blazing...