Any "I can't believe you wore that to my party" ideas?

I’ve been invited to an “I can’t believe you wore that to my party” party. I’ve thought long and hard about this and had several conversations with people about this. Dressing up as a giant boob, bestiality or a swearword aren’t exactly my cup of tea, does anybody have any classier ideas? Classy but still offensive? I’ve been in a quite mellow mood lately so I’m needing some help.