Listen as former curator Dedo von Kerssenbrock-Krosigk describes this trick goblet, which holds a separate "straw" whose finial resembles the head a stag. To drink from it, one has to suck the liquid through the mouth of the stag while covering a hole in the stem of the vessel. Thus, this glass is a perfect device to fool a guest during a drinking game. The Germanic countries have a long tradition of playing elaborate games in high society.
David Whitehouse describes the same goblet. When you try to fill this glass with liquid, some of the tubes and bulbs remain empty. If you try to drink from the glass, the air in the tubes makes the liquid gush out when you least expect it.