BUTTER 13 x 9-inch baking pan.
MICROWAVE 1 1/3 cups butterscotch morsels, semi-sweet morsels and peanut butter in large, uncovered, microwave-safe bowl on HIGH (100%) power for 1 minute; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until morsels are melted.
ADD pretzels, peanuts and Raisinets; stir well to coat. Spread into prepared baking pan.
PLACE remaining butterscotch morsels in small, heavy-duty plastic bag. Microwave on MEDIUM-HIGH (70%) power for 30 seconds; knead. Microwave at additional 10- to 15-second intervals, kneading until smooth. Cut tiny corner from bag; squeeze to drizzle over candy.
REFRIGERATE for 1 hour or until firm. Break into bite-size pieces. Store in covered container.