2 ounces Scharffen Berger 72% Signature Dark Chocolate (1 bar)
Place the Greek yogurt in cheesecloth and squeeze out as much liquid as possible. Place the cheesecloth and yogurt in a small colander and place in the refrigerator overnight on a shallow dish to drain more liquid.
Wash and dry berries thoroughly. Set aside.
Add yogurt, sugar, vanilla, and butter to a medium mixing bowl and beat until very smooth (about 3 minutes).
Dip berries in the yogurt dip and place on a parchment lined baking sheet to cool/harden.
Melt chocolate in a heat proof bowl over a small saucepan with about an inch of simmering water. Pour the chocolate into a plastic piping bag or make one from parchment paper rolled into a cone with a tiny tip cut off.
Use the small tipped piping bag to draw ghost eyes and a mouth on the dipped berries with chocolate. Allow to cool/harden completely before serving.