Line a baking sheet with parchment paper or a silicone baking mat.

Separate the Halloween sprinkles into small bowls for easy access.

In three separate microwave-safe bowls, place the purple, green, and orange candy melts.

Microwave each bowl one at a time, in 30-second intervals, stirring after each interval until the candy melts are fully melted and smooth.

Using a fork or dipping tool, dip each Oreo cookie into the melted candy until fully coated. Allow the excess candy to drip off before placing the cookie onto the prepared baking sheet.

Dip 4 Oreos in purple, 4 in green, and 4 in orange candy melts for a colorful variety.

While the candy coating is still wet, generously sprinkle the Halloween sprinkles over the top of each Oreo. Get creative with your sprinkles to make each Oreo unique and festive.

Allow the decorated Oreos to sit at room temperature until the candy coating has completely hardened. This can take about 30 minutes to an hour. If you're in a hurry, you can place the baking sheet in the refrigerator for about 15 minutes to speed up the process.

Once the candy coating has set, arrange the Halloween Oreos on a festive plate or store them in an airtight container until ready to serve.