This potion bottle is one of my kids' favorites. It features a green gem, created using my Faux Gemstone technique which is set into a large black blob-like medallion made from polymer clay. The medallion features tentacles which wrap around the bottle somewhat. Two of them have been extended and wrapped around the neck of the bottle. A similar green gem was set atop the cork stopper.
Although polymer clay does not permanently adhere to glass, the clay here has not been glued to the glass because it is wrapped around the glass, keeping it in place.