Line a large tray with parchment paper and set aside. Gently separate the oreos by slowly twisting them apart. (Some will break, it's okay, just try to be gentle)
Separate the milk chocolate into 3 parts (this is to keep it from getting hard while you decorate) and place each section in a microwave safe bowl.
Into each bowl of chocolate chips add about 1/2 teaspoon vegetable oil or shortening (more if needed to thin it even more).
Melt in 20 second bursts in the microwave (Microwave 20 seconds, stir 20 seconds, etc.)
Be patient when melting and stir well in between bursts to avoid burning the chocolate.
Dip one end of the lollipop stick into the melted chocolate and press into the cream side of the oreo.
Separate the oreo THINS and remove the creme filling. Break the thin oreos in half (again there will be some that don't work out; thats okay!) and then dip each edge of the oreo thins in chocolate and press into the creme filling on either side of the lollipop stick.
Using a spoon, smear a little more melted chocolate on the other half of the oreo and then gently press on top of the "bat wings" and hold. Let harden completely (about 10-15 minutes).
Gently spoon melted chocolate over the top of the oreos and the "wings". Lightly tap the oreo pop on the edge of the chocolate bowl to smooth the chocolate. Scrape the bottom side of the oreo pop against the bowl to remove excess chocolate and then place on the prepared parchment lined tray.
Gently place two edible eyes into the melted chocolate and if desired, add some sprinkles above the eyes.
Allow to harden at room temperature.