Here are some interesting facts about the king cobra: 1)The lifespan of the average king cobra is about 20 years. 2)The king cobra is the longest venomous snake in the world. 3)The king cobra's venom is used in some medicines to relieve pain. 4)The king cobra is the only snake that builds a nest for its eggs. 5)The king cobra can spot movement from up to 300 feet away.