The term 'Dangerous Slitherer' is a reference to the ADDER, a venomous snake native to Europe and parts of Asia. It is also known as the Common ADDER or Vipera berus, and is the only venomous snake species found in Great Britain. The ADDER is a relatively small snake, usually growing to a maximum length of around 90 cm. It is characterized by its distinctive zig-zag pattern along its back, and its venom can cause severe pain and swelling if left untreated.