It's a fairly common tone that seems to pop up on heavily overdriven solos w lots of distortion (is that redundant) but I have no idea what it is. On this video Katana Demo for instance, you can hear it between 5:13-5:17 and also between 5:50 and 5:55 (and lots of other places). I first remembering hearing it from Van Halen (e.g., right from the start of "Ain't talkin bout Love"). It sounds so different from all the other notes being played. I'm wondering if it's the sound of an overdriven fuzzed out non-fretted harmonic, but really I have no idea. Thanks.