There were two images from Michelangelo's Last Judgment that especially singed my six-year-old brain. One is of a condemned sinner, newly arrived in Hell and just beginning to comprehend where he is and where he will be spending a hopeless eternity. He clutches his left hand over his left eye in denial while his right eye remains frozen open in horror. The other is of Charon, the pop-eyed demon ferryman who is whacking a cowering herd of the damned with the oar of his boat. When the neighborhood kids came over to play, I used to take out the book with these pictures in it and drag it outside where I would open it up to that page (page 229) whereupon we would all scream, slam the book shut, and run away only to creep back and do it again. It was a big thrill, and it helped that all the neighborhood kids were Catholic (my family is undecided) so they could fill me in on any gory details that Michelangelo might have left out.
From that same book, The World's Great Religions (Simon and Schuster, 1957) there are a couple of other indelible images that I still carry around. The most fun for me was the brightly colored fold-out page illustrating various Hindu gods, goddesses, and demons. I used to sit with that page open for hours copying and tracing and studying the details. My favorite was Kali, wearing a necklace of little heads and waving her many arms (one of which was holding a severed head) as she sat on an unnamed moon goddess's belly sticking out her tongue.
The image that really truly frightened me (as opposed to fun-scary) was a small sixteenth-century etching of people being burned at the stake. I couldn't take my eyes off it. At the time my father worked for the Alcoa Corporation. Once in a while he would come home from work with a grave face and I would hear him and my mother speak in hushed tones about someone being "fired." For quite a while I lived with the awful fear that my father too would be "fired." I thought that meant the people from his job would burn him at the stake.