Beat the peanut butter and butter with an electric mixer in a large bowl until smooth. Beat in the sugar and vanilla. Cover and refrigerate for 30 minutes. Roll chilled dough into small, eyeball-sized balls and place on 2 baking sheets lined with wax paper. Refrigerate for another 30 minutes.
Melt the white chocolate and shortening in a microwave-safe glass or ceramic bowl in 30-second intervals, stirring after each melting, for 1 to 3 minutes (depending on your microwave). Do not overheat or chocolate will scorch. Dip each eyeball into the white chocolate and transfer to the waxed paper until the chocolate has set. You can chill them in the refrigerator.
Stir a few drops of blue food coloring into the remaining melted white chocolate. Make a round iris on the top of the cooled eyeball and press a mini chocolate chip in the center for a pupil. For an extra spooky bloodshot eyeballs take a toothpick dipped in red food coloring and make squiggly lines on the eye.