I found a Halloween costume for my dog, but they don't make it in his size

They've got one that would fit Berkeley, though.

Dressing cats up in stupid costumes is so passé these days. What you really want to do is buy your dog a skeleton costume (via Boing Boing).

Obviously.

The costume also comes in medium and small. The web site doesn't mention what that actually means, and unhelpfully uses the same dog to model all three, which to me is an opportunity wasted. I'd really like to compare a great dane, a labrador and a yorkshire terrier, all wearing the same outfit, to see which looked scarier.

I'm betting on the terrier.