Line a rimmed baking sheet (I used two 11 x 15 pans) with parchment paper so the paper extends over the edges for easy removal later. Adjust the ingredient amounts for a larger or smaller sheet as needed.
Melt the candy coating according to package directions; I used the microwave.
Pour the melted dark chocolate coating onto the parchment paper and spread it evenly using an offset spatula until about ¼ inch thick.
Spoon dollops of melted white candy coating over the dark chocolate and swirl gently with the tip of a knife, or bamboo skewer to create a marbled effect.
While the candy coating is warm, sprinkle your candy toppings, candy eyeballs, and Halloween sprinkles evenly across the top.
Allow the bark to cool and harden for about 30 minutes. Once set, lift the bark out of the pan using the parchment edges and transfer it to a cutting board. Cut into desired serving size pieces.
Store Boo Bark in an airtight container at room temperature for up to two weeks.
When ready to gift or serve, wrap individual pieces in cellophane bags, pack them in mini treat pails, or fill a decorative tin for easy gifting.