Sibylla

"Nam quidem Cumis ego ipse oculis meis
vidi in ampullam pendere, et cum illli pueri dicerent:
Sinylla ti theleis?. Respondebat illa: apothanein thelo."

"At Cumae I have seen with my own eyes the Sibyl hanging in a jar,
and when the boys asked her 'What do you want?'
She answered, 'I want to die.'"

- From Petronius Arbiter. Satyricon

Sybil of Cumae guided Aeneas through Hades. Therefore she had been granted immortality by Apoll.
but because she forgot to ask for perpetual youth, she shrank into a withered inhuman thing.