The Egg is a unique vehicle used by mostly the Burrowers to traverse the inside of Cutter. Domesticated vangolas pull it through the passages of the mountain.
The shape of the Egg does not resemble an actual egg. It is named after the feeling almost every valturo feels when they exit the vehicle after their journeys. It is made from shells of dead vangola to fit nicely into the mountain passages. Using vangola shells also makes them more durable within the smaller shafts. Small sheets of transparent intal are added at the front and back to see something of their path and to control the vangola.
Depending on the task, the Egg is outfitted differently. The miners and scavengers usually take generic equipment with them. It is used to collect anything they encounter. The hunters take some generic equipment with them, but they are mostly outfitted with weapons to take down any crazed vangola. They all take special tranquilizers to subdue young vangolas if they run into one.
The travel time the Burrowers take with these vehicles is usually a few hours or a couple of days. It is hard to carry enough food and water with you for an extended period. When the miners go on longer missions, they link up one or more additional Eggs. This way, they can carry more food, water, and equipment to their destination and hopefully more minerals, crystals, and meat on the way back. The most extended expedition was to the Cutter's other side. It took a convoy of 10+ Eggs and valturos of various organizations to make it to the other side.
Yes, we call it egg because it is cramped, you can not see anything, and it is as hard to get out of it as when you are born