The term 'scary snake' can be broken down into three crossword solutions: ASP (3 letters), ADDER (5 letters), and RATTLER (7 letters). ASP stands for the venomous snake species, Vipera aspis, which is found in Europe and North Africa. ADDER is another name for the Vipera berus, a venomous snake species found throughout Europe and parts of Asia. Lastly, RATTLER is a common name for the Crotalus genus of venomous snakes, which are found in North and South America.