A Musicblock GNG is a kind of Musicblock. It can only be found by playing with the Special Item That Only Beta Testers Get. Whether this is a rare drop, or a one-time event is unknown. It is rumored that you may get more than one, but it hasn't been substantiated.
was anybody lucky enough to extract GNG more than once?
and how many times you had to procrustinate your pickle to get the first GNG?