That tattoo on your lower back is likely to appall your mother. Just like her pink hair once appalled your grandmother. To appall is to shock and disgust.
Appall comes from an Old French word meaning "to make pale." If a gory scene in a movie appalls you, you're likely to turn pale. The word appall always carries with it the feeling of disgust. You might be shocked by a loud noise, but in order for it to appall you, it would probably have to come along with a really foul smell or a gruesome scene.