SPRAY 13 x 9-inch baking pan with nonstick cooking spray.
COMBINE cereal, pretzels, peanuts and caramels in large bowl.
MICROWAVE morsels in medium, uncovered microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. Morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring until smooth. Pour over cereal mixture; stir to coat evenly.
SPREAD mixture into prepared baking pan; let stand for 20 to 30 minutes or until firm. Break into bite-size pieces.