Critics have called the stories, many of which feature macabre topics such as murder, disfigurement and cannibalism, "sick... repulsive", and "really disgusting... not appropriate for children". The nightmarish artwork by Stephen Gammell has also been a subject of criticism.

According to Marshall.edu, the main reason why the books were banned was the contents were violent. Wikipedia describes Gammell's nightmarish artwork as another contributing factor to parents' objections to books. Gammell's

of disturbing, gruesome, and scary characters were not appropriate for children.