PLACE chocolate and butter in saucepan; cook over low heat until melted, stirring frequently; set aside.
SPREAD bottom of each cookie with 1 tsp. peanut butter; dip into melted chocolate mixture. Immediately press 2 pretzel twists on chocolate for "frog legs" with wide part of pretzels facing outward. Place, pretzel-side down, on wax-paper-lined cookie sheet.
ATTACH candies for "eyes" using remaining chocolate mixture. Let stand until chocolate is set.
Note: Candy eyes can be attached to frog with additional peanut butter, if desired.