Okay this has a really cool backstory that blew my mind (since I’m a big E6 fan too). In the early 2000s, Isaac Brock teamed up with Elephant 6 members Julian Koster (of Neutral Milk Hotel and The Music Tapes), Bill Doss (of The Olivia Tremor Control), Robbie Cucchiaro (of The Music Tapes), and Kevin Barnes (of of Montreal) and formed a sort of super group only known as “Mysterious Band”. According to people in the E6 facebook group, this band played a few more times with more people.
This recording was released on a compilation called Border Music…Flicker Of A Smile - Athens Experimental (U.S. Pop Life Vol. 10), which was only released in Japan.