Mix sugar, peanut butter, and butter until blended, kneading with hands if necessary.  Shape peanut-butter mixture into 1-inch balls; place in jelly-roll pan.  Cover and refrigerate until firm, about 2 hours.

When peanut-butter balls are firm, melt chocolate pieces and shortening until smooth, stirring occasionally.  Remove from heat and cool slightly.

Using a toothpick, carefully dip peanut-butter balls, one at a time, into chocolate mixture, making sure to leave a small amount of the peanut-butter mixture showing on top to resemble an eye.  Place on waxed-paper lined cookie sheet. Remove toothpick; with spoon gently smooth over toothpick hole.  Refrigerate until coating is firm, about 1 hour. Makes 3 1/2 dozen.