It's cute to see the kids trick or treating in all the costumes! However, it's scary for pets. They don't understand what's going on. Doorbell ringing constantly, knocks on the door, strange looking people showing up. Cats usually will run and sometimes right out the door. Dogs will bark, they're protecting their people and their home, it's what they should do! Help them out. Put the cats in an enclosed room temporarily so they feel safe with their food, toys, litter. For the dogs they need to see what's happening, locking them up in a room will only cause more anxiety. Set up a dog gate that keeps them away from the door but they can still see that their people are ok, and the treaters are safe from the dog. Also, have food, water, some toys and their bed in the room with them. Whatever you do, don't yell at your dog for barking at strangers. You are their person, they're protecting you.