Massive Attack, arguably one of the most influential electronica acts of the last ten years, may be slimming down from a three-piece into a duo.MTV Europe is reporting that Mushroom, one of the co-founders of Massive Attack, has left the band after months of media speculation about creative conflicts with Daddy G and 3D. Massive Attack played several shows last weekend in Germany as two-piece, and there's talk that Mushroom might have actually left the band earlier in the year to pursue his own solo career. A publicist at Massive Attack's U.S. label, Virgin Records, could not confirm the reports, saying that the label was unaware of any shake-up with the Massive Attack camp. "Mushroom" Vowles, "Daddy G" Marshall, and urban artist 3D formed Massive Attack in Bristol, England back in 1987 and released its first single "Daydreaming" three years later. Massive Attack released the critically acclaimed "Mezzanine" LP last spring.