Back in '73 or so, Return to Forever played at the old Bayfront center theater (now the Mahaffey theater). A friend of mine in band had gone to the show and we were standing in the bandroom talking about it. My buddy was raving about the show. John happened to be walking by (we hardly knew him) and asked my friend what he like about the concert. My buddy started raving about the band and musicianship, and then noted Stanley Clarke's awesome performance. John went to the back of the room and selected one of the several never used acoustic basses (we didn't have an orchestra and never knew why those basses were there). He brought it down and tuned it a bit, then unleashed a two minute stream of awesome bass playing. Afterward, as my buddy and I stood there with our jaws on the floor, John casually remarked "Yeah, Stanley was a student of mine...." and walked off.
A couple of years later RTF was back at the same venue. Clarke started playing a solo improv on acoustic bass and broke a string on his bass. He jokingly asked the audience "Can anybody here play one of these with a broken string?" "I can" came a shout from the audience, as John strode up to the stage. Clarke greeted him warmly, introduced him, and I believe they did a duo together.
We used to dress up and sneak into lounge gigs that John played around town (we were underage). He used to have a great duo with a guy named Vic Suchin (if I recall correctly).
John's a monster.