Which Metallica song's lyrics are inspired by H.P. Lovecraft's 'The Shadow Over Innsmouth'?

Metallica's “The Thing That Should Not Be” is the song whose lyrics draw heavily on H. P. Lovecraft's The Shadow over Innsmouth.

The track appears on Master of Puppets, released in 1986, and uses imagery from Lovecraft's Cthulhu Mythos. References to hybrid children, a fallen city, an ancient being beneath the sea, and a cult-like awakening echo the atmosphere and ideas of The Shadow over Innsmouth and related Mythos stories.

The song is not a literal retelling of the novella. Its lyrics also invoke broader Lovecraftian concepts, including Cthulhu and the Great Old Ones, while the famous “not dead” couplet alludes to another Mythos text, The Nameless City. That wider blend is why the song is often described as Lovecraft-inspired rather than a straightforward adaptation.

A frequent mix-up is “The Call of Ktulu,” Metallica's earlier instrumental from Ride the Lightning. That song is also Lovecraft-related, but “The Thing That Should Not Be” is the canonical answer for the specific Innsmouth inspiration.