As is made clear by the song The Call Of Ktulu on the second studio album Ride The Lightning (Studio Album), Metallica have some interest in the writing of HP Lovecraft. The lyrics of The Thing That Should Not Be seem to fit well with the HP Lovecraft Cthulhu mythos, including lines such as "Great old one" which may be a reference to the Great Old Ones often appearing in Lovecraft's works, "Hybrid children watch the sea, Pray for father, roaming free" which may refer to the people of Innsmouth (a key location in the Cthulhu Mythos) and "Out from ruins once possessed, Fallen city, living death" a possible reference to Cthulhu himself as he resides in R'lyeh (another key location in the Cthulhu Mythos).