Mr. Crowley is a pretty black song about an English occultist and vampire, Aleister Crowley, who lived from 1875 to 1947. Apparently he enjoyed drinking cats' blood and encouraged a guy called Raoul Loveday who died at his Abbey of Thelema to do the same. The line: 'Won't you ride my white horse?' is a heroin reference. After all, Crowley was addicted to opium.
Allegedly, he once snorted a line of live ants. *shudder*
Randy Rhoads' autopsy report, which can be found with a minor amount of digging on a fansite, specifically the summary of the external body examination. After all; while everyone on the plane was supposedly dead on impact, the plane still exploded when it crashed...
A few songs on No Rest For The Wicked ("Devil's Daughter", "Fire In The Sky" and especially "Bloodbath In Paradise"). "No More Tears" is this once you know what it's about (which many people, either fortunately or unfortunately depending on how you look at it, don't).
"Mr. Tinkertrain" is sung from the perspective of a pedophile and its lyrics are highly disturbing, with the narrator gloating about the mental scarring he inflicts on his victims and making references to abduction, sex toys and sexual slavery. Worst of all: he gets away with it.
The Down to Earth cover art could definitely give you nightmares, thanks to him being HORRIBLY disfigured, and especially the uncensored version of the Gets Me Through music video, which has pigeons bleeding to death! And even worse, one of the scenes of the video has Ozzy lying dead, his little toes bleeding because of supposedly stepping on glass, and a sinister face shows up from out of nowhere after Ozzys emotionless supposedly dead face. Thats going to give anyone nightmares. Especially Facing Hell, which the lyrical content could give folks the heebie-jeebies. Worse than that, the line of an evil one taking the victim as mentioned in Facing Hell is ABSOLUTELY GOING TO GIVE PEOPLE NIGHTMARES. And Dreamer, the 2nd single that has a wholesome meaning, but the cover shows Ozzy showing his one eye like A TRIANGLE! Seriously, Down to Earth is probably Ozzys biggest attempt at nightmare fuel.