I've recommended a "this is my costume" t-shirt before, but I like this one better.
This is such a slacker costume that I can't totally recommend it. But, on the other hand, have you ever worked in one of those offices where you hate everyone and they all dress up and want you to be a part of it? I can imagine getting some satisfaction out of being the smug a-hole that showed up in this.
Kinda funny, kinda douche-y, this 'costume tee' is perfect for all the lazy Halloween revelers that want to participate in the holiday. But only a little bit.