Monster Rating of 16. If it gets any hits on you, roll a die to see if it is poisonous. On a roll of 4, 5, or 6 it is poisonous. If you take any hits from a poisonous snake, but still survive, your strength is cut in half for the rest of the time you are in this dungeon. Snakes are not affected by poison.
After you kill the snake, roll one die to see if its mate comes looking for you. If you roll a 1, you must fight another snake.
If this is not an "exit monster" instead of fighting you may try to run away.