Step 1) Cream butter, powdered sugar and extracts. Add flour and corn starch. Cover and refrigerate at least 30 minutes. Preheat oven to 350°F.
Step 2) Roll dough into 1-1/2 inch balls. Place on ungreased baking sheet. Flatten each cookie by pressing gently with fingers.
Step 3) Bake 10 to 12 minutes, just until bottoms are lightly browned. Cool cookies on wire racks.
Step 4) Melt semi-sweet chocolate chips with oil. Dip half of each cookie in chocolate. Place cookies on wire rack or wax paper to allow chocolate to harden. While chocolate is still soft, place candy corns for fangs and icings for eyes on cookies.