I like to go as an endangered species! Excuse the wrinkled, dog-hair covered t-shirt. I forgot I had it on.
One of my dogs was not very cooperative when we tried to take his picture. He wouldn't keep his ears in the alotted holes. So, his costume head kept falling back. (look closely you'll see he was black nose at the very bottom of the picture and his bangs covering his eyes. That way, you can try to imagine how he looked, though.
My friend made her dog, Sara, a Lion costume. Sara's so proud in her costume, unlike my dog, Bebe. He's usually just as smiley as Sara, but maybe he wanted to be a Lion instead of a Sock Puppet.