Pulicenella 'a coppa Sant'Elmo piglia 'o purpo a mmare
Punchinello is able to catch an octopus standing on the hill of St Elmo Castle. Punchinello is one of the most famous symbols of Neapolitan culture. Mostly everyone has once herd about him, but maybe they don't know he's a cunning man.
This motto uses a metaphor to say that Punchinello is able to obtain whatever he wishes even in extremely difficult situation where anyone else would fail. St Elmo's hill is high above the sea level, so it is impossible to catch an octopus from up there. Punchinello, he would succeed.
Out of metaphor: there are some persons who are capable of obtaining anything using tricks or deceiving some fellows.