Preheat oven to 400 degrees. Combine cheese and crab ina small bowl. Divid crab mixture among the upside-down mushroom caps, stuffing the mushrooms. Carefully lay 6 sheets of phyllo dough on top of one another, brusing every other sheet with melted butter. Cut phyllo lengthwise down the center and cut each half into 3 pieces to make 6 rectangles. Place a mushroom, cheese side up, in the center of each square. Season with salt and pepper. Lift sides of pastry over mushrooms to resemble small bundles and form a "neck", pinching edges together to seal. Repeat the entire procedure 2 more times.