For many people Halloween is an occasion for kids to play together and to collect candies in funny costumes. There is certainly nothing wrong with that as long as their parents ensure their safety. 

But, glorifying evil by dressing like the devil or a witch can be dangerous for children’s spirituality according to father Vincent Lampert, a Vatican-trained exorcist who is now a parish priest of the Archdiocese of Indianapolis. 

Wearing costumes of monsters, demons and witches can develop into an interest in magic and occultism. It is a sin against the first commandment to consider magic to be more important than God.

Besides, some costumes are very realistic and full of violence and blood which can make children to have nightmares.