Below are 40 of the funniest, miku costume cutest and all-around best dog Halloween costumes-and you can find all of these great dog costumes for Halloween at PetSmart. Then wear your costume again for Halloween or another day of cosplay. 21. All day long, participants dress and talk like pirates. What a grand day! We’d like to extend a warm welcome and introduce you to the variety of five-star quality cosplays that we have to offer.