While Catholicgauze wishes everyone a happy, safe night of harmless and healthy fun, the international backlash against the American holiday of Halloween is now being fought not by the French who gave up and now are co-opted but by the British, the semi-official newspaper of the Holy See, and Russia.
The old Catholic tradition for Halloween was/is to dress up as one's favorite saint. For those who want to combine old and new or just be really retro then they should consider dressing up as Saint Christopher for Halloween.
Saint Christopher is consider the patron saint for travelers and is best known for the medallion of his some people wear on trips. However, in some ancient depictions he is shown with a dog head. The dog head stories are based on the origin story that has Christopher being a warrior from the outskirts of the Middle East. Ancient Greek tradition held that those on the rims of the world were barbarians who talked like sheep and dogs making a "bar bar" sound. Add the European imagination and these barbarians were given dog heads. One legend has Christopher converting and then God making him fully human by giving him a normal head.
The legend of dog heads was adopted into the Christian cosmological world view. Even in the age of Marco Polo many Christians thought the ungospelized world was filled with quasi-humans with faces on their backs, dog heads, and other weird traits.
Today Saint Christopher's existence is disputed and the Catholic Church is playing it safe with toning down but not stopping the cult of Saint Christopher.
Or, one can go as the badass Saint Michael the Archangel