The term 'CERTAIN VIPER' is a collective term for two different species of venomous snakes. The first is the ADDER, which is a venomous snake found in Europe, North Africa, and parts of Asia. It is usually brown or grey in color and can grow up to 1 meter in length. The second is the ASP, which is a venomous snake found in North Africa and the Middle East. It is usually black or dark brown in color and can grow up to 2 meters in length. Both species are highly venomous and should be avoided.