Jaco. A total nutter. He walked up to Zawinul and said, "Hello, my name's Jaco Pastorius and I'm the best bassist in the world". That takes cojones. Especially to a guy like Zawinul, who didn't suffer fools gladly.
Thing is, it was as close to being true as these claims ever can be. (They're always basically false, in my humble opinion. And I'm talking about probably my favourite player on electric bass, at least as far as jazz goes.)
Funny thing, though. To my great surprise, Victor Bailey always insisted that he had very little in the way of improvisational ability. Bailey had no axe to grind, he was himself a phenomenal bassist, and he really rated Jaco's work. Simply, he said that all Jaco's parts were written out (including his solos) and that he'd rehearse them hundreds of times until he had them note perfect. It doesn't make Jaco a lesser bassist, but it does slightly change my view of him.