The video for Soul Asylum's "Runaway Train", which is about missing and abducted children, can cause parents long-term nightmares. The last few seconds, which depicts the theft of an infant from its mother, who only looked away for a second, is downright horrifying.
StickyFingaz's album Blacktrash:The Autobiography of Kirk Jones is full of Adult Fears. The idea behind the album is a pretty big adult fear: getting out of jail and trying to reintegrate into society and makes ends meet while being part of the urban poor. Inside of that bigger concept, the album deals with a lot of other Adult Fears like going back inside ("Why", "State vs. Kirk Jones", and the skit at the end of "Licken Off in Hip Hop"), his girl finding someone else while he's doing time ("Cheatin'"), and seeing people he cares about heading down the same path of violence ("Baby Brother").
Much like the Soul Asylum example above, the video for "Abduction" by Dirty Rotten Imbeciles is also about abducted children, and neither the video or the lyrics pull any punches. If the concept or the words behind the song didn't scare you, the child screaming for her mother after being abducted from playing in the sandbox definitely will.
The first phrase in the chorus of Rammsteins "Donaukinder" ("Wo sind die kinder?") translates to "Where are the children?". The narrator watches all the wildlife in his town die, smells them rotting in the river, and realizes his kids are missing. The song is about a real-life chemical spill in Baia Mare, Romania, where several (estimated to be 100) tons of cyanide-laced water was accidentally discharged into the Danube and Somes rivers when a dam burst, and from there the Tiza river. How many kids were swimming when the incident occurred?
Cormorant loves to invoke this trope, having multiple songs where Infant Immortality is outright averted. And aside from that their song "Junta" plays on the fear of losing one's child in a mass shooting while their daughter is raped elsewhere, "Daughter of Void" has a child lead astray and killed by a Qalupalik, and "A Howling Dust" has a child mentally scarred after having a hand in the death of an innocent man.
Creature Feature usually deals with more fantastic forms of horror, but "Bound and Gagged" brings to light any parent's worst fear: someone kidnapping their child and threatening to kill them if their demands aren't met.
Gustav Mahler's song cycle Kindertotenlieder ("Songs on the Death of Children") describes the emotional fallout of losing a child in excruciating detail. The Reality Subtext makes it even worse, as a few years after the cycle was composed, Mahler's own two-year-old daughter died of scarlet fever.
In this weather, in this storm, I would never have let the children out, I was anxious they might die the next day: now anxiety is pointless.