That skull will be a man's skull. They cut the upper part of the skull and consume the food in that. In ordinary days, they don't visit public places. They come out during Pushkar and Kumbmela times. How they come to these events is a big question mark? After the event, they walk for one kilometer or so and disappear suddenly. Some believe that this is due to Nano Technology. With this technique, they turn into small objects and disappear. This technology was written in many books in the past, some says.
Aghoris don't eat anything for years sometimes. They involve in meditation and forget all the pleasures of life. In the Kumbmelas, they bring holy threads from air. Some says, it is a simple magic trick. Some argue it for nuclear transmutation. But, spending months together in Himalayas is not a small thing.