Shell 6 hard cooked eggs. Cut in half, lengthwise. Remove yolks. Mash and add 1/2 cup finely chopped cooked beets, 1 tablespoon prepared horseradish, 3 tablespoons mayonnaise, 1 1/2 teaspoon salt and 1/4 teaspoon pepper. Mix lightly and chill. To serve, fill mixture into the halves of egg whites.