I always laugh whenever I see a pet in a Halloween costume. But then I also always wonder what the pet thinks about it. It's got to be unuusal, to say the least, for an animal to find itself wearing a cape, tuxedo, or eye patch. This year, it is estimated that about 16% of Americans will dress their pets in a costume for Halloween. Here are some of the most popular Halloween costumes for pets, according to Petco and the National Retail Foundation.