I don’t believe this item is from any vintage porcelain tea set - German or Japanese. It looks amateurish, especially the teeth. I think this is the result of someone with a modicum of talent copying the features from an authentic cup, perhaps for their own amusement. It doesn’t have collectible value in terms of vintage Halloween.
02/22 Update: I’m glad no one seemed to be fooled by this fake. It sold for $58.00.