Line a large baking sheet or workspace with parchment paper and set aside.
Place candy melts in a medium, microwave safe bowl.
Melt on 50% power for 1 minute, then stir. Return to microwave for 30 second intervals until candy is completely melted and smooth. Resting the cookies on a fork, carefully dip cookies into the candy melts and use a small spatula or spoon to coat the entire cookie with the candy melts. Tap the fork lightly against the side of the bowl to get rid of excess coating before placing the cookie on parchment paper to set. Repeat with remaining cookies.
If you are working in a cold kitchen, or this process takes too long, the candy melts will begin to harden. If this happens, simply return the bowl to the microwave for 30 seconds or more to warm them up again.
While the cookies are cooling, place the pretzel twists on one end of the cookie to create antlers. Add the candy eyes underneath and then a Mini M&M for the nose. If needed you can use a bit of extra candy melts to adhere the decorations to the cookie!
Use the black decorating gel to create smiles on your Reindeer.
Allow cookies to harden completely before serving.
Store at room temperature in an airtight container for up to three days.