PLACE chocolate and butter in saucepan; cook on low heat until chocolate is completely melted, stirring frequently. Set aside.
SPREAD bottom of each cookie with 1 tsp. peanut butter; dip bottoms into the melted chocolate mixture. Immediately press 2 pretzel twists into the chocolate for the "frog's legs," with the wide part of each pretzel facing outward. Place, pretzel sides down, on wax-paper-covered baking sheet.
ADD candies to tops of the cookies for the "eyes," using the remaining chocolate mixture to attach candies. Let stand until chocolate is set.