A Yellow (or Gold) Ringed (or banded) Cat (or Mangrove) Snake at night above the Menanggul River, Sabah, Borneo, where it is known as Ular Tiung cincin.
The lower pinkish area is the vent, and the slit toward the top is the umbilicus, where the snake was attached to it's yolk. Before it is 1 year old this mark will be gone, so we know this is a young-of-the-year.