Last Halloween, my granddaughter invited me out to her neighborhood pet store where they were having a "cutest dog-costume" contest. She dressed her two Chihuahuas as a pirate and a vampire. Among the many competitors were a wooly little lamb and a bumblebee. The contest winner was a handsome Great Dane in a cowboy outfit.
When I googled "Halloween dog costumes", I discovered it is really big business! So, enjoy the fun while it lasts.
I personally have never had a Halloween costume. Although, once I wore a pair of Garfield Deely-Bobbers to a party. As I remarked at the time, "There really are so few functions where one can wear their Deely-Bobbers!"