Line 2 baking sheets with wax paper. Beat peanut butter and butter in large mixer bowl until creamy. Beat in powdered sugar until mixture holds together and is moistened. Stir in chopped Butterfinger. Shape into 1-inch "eyeballs." Place on prepared baking sheets. Freeze for 1 hour.
Melt morsels and shortening in large, uncovered, microwave-safe bowl on Medium-high power for 1 minute 30 seconds; Stir. Morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until melted. Remove one baking sheet of frozen "eyeballs" from freezer (keep other sheet in freezer until ready to use).
Dip one "eyeball" into melted morsel mixture using a wooden pick or skewer. Shake off excess and return to baking sheet. Gently press 1 Raisinet on top of "eyeball" to make a "pupil." Repeat procedure with remaining "eyeballs" on baking sheet. Refigerate until coating is set. Repeat with remaining sheet of "eyeballs" and coating. You may find it necessary to reheat morsel mixture before dipping second batch. Before serving, pipe decorator icing around eyeballs to create bloodshot markings. Store in covered container in refrigerator. Best served cold.