Melt the candy melts in a microwave safe bowl. Using a fork to support the cookie, dunk the sandwich cookies into the bowl and coat in chocolate. Using your fork, tap off any excess chocolate. Transfer onto a parchment lined baking sheet. Repeat until all cookies are covered in chocolate. Add two mini marshmallows to the tops of the cookies, these will be the ears. Add candy melts to the middle of the cookies. Add the candy eyes. Take a Ziploc bag and fill it with the remaining chocolate, snip the end and dab a small amount onto the M&M and place on the candy melt, this will act as the glue. Repeat steps until all cookies are polar bears. Chill for 30 mins, until chocolate is solid, enjoy.