Os Mutantes Guitars

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. Zach