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Nightmare Fuel: Low
Low's album with the highest terror rating is Trust, which is largely about heroin addiction and was recorded in a desanctified Catholic church. It features:
"The Lamb": Ghostly voices singing "sha-na-na," percussion that sounds like chains being slammed against a concrete floor, and the lead singer shouting "I AM THE LAMB, AND I AM A DEAD MAN!"
"John Prine." What it has to do with John Prine isn't clear, but its lyrics are soaked in self-loathing and it ends in a terrifying, repeating "na na na na."
"Shots and Ladders." Lyrics about someone who's chronically ill, if not dying. The music itself sounds like the recording equipment was falling apart as they were using it.
Secret Name is by and large about the sacrifices that people make for their faith. (Two out of three of the band members are Mormons who are married to each other, and the name of the album references a concept in the Mormon wedding ceremony.)
"Don't Understand." Dissonant tape loops and lyrics that are apparently about a child abductor.
"Home." Just a simple, slow guitar line and a falsetto voice singing "Everybody wants to go home, even when they're old, even when they're small." Terrifying.
Their B-sides compilation includes a number of songs apparently too terrifying for albums, including a Jandek cover where the singer sounds half dead.