Cobra or Viper is a term used to refer to two different types of venomous snakes. The Cobra is a large, highly venomous snake found in Africa, Asia, and the Middle East, while the Viper is a smaller, more agile snake found in Europe and North America. The term 'AUTO' is a four-letter word that can be used to describe both of these snakes, as they are both capable of striking their prey with lightning speed.