It's a distorted guitar through a very fast tremolo effect, something with the depth turned up so much that it cuts in and out of the sound, then the rate turned up so much as to be a very quick cutting in and out. Andrew

===== Original Message From Zachary Steiner <zsteiner@butler.edu> ===== I know Tropacalia artists have been discussed here before, so here goes...On track 7, "Bat Macumba," from Os Mutantes's self-titled '68 album, what is that weird broken up guitar effect? It sounds like a modern effect in which bits are digitally removed, but bits were something else entirely in 1968. It's just a really neat sound and it's been driving me crazy what it is. By the way, the album is weird and wacky fun; highly recommended for any one who has already checked it out.