Guard Dog and as far as these fakes go, I was almost taken in!
I mean, just took at him! What a splendid beast, I'm sure you'll agree!
If Valve hadn't sent another "twit" out a few minutes later saying it was a joke then I'd still be wondering if it was real or not, despite not being able to click on any of the links shown on the page. I especially liked the achievements such as the "Loch Ness Monster" or the rather disgusting "Go Lassi-ed"
Then, even more surprisingly the TF2 blog now shows a "patent pending" letter for the Guard Dog character - could this mean we might actually see this in the game?
I think it's really great that Valve has kept TF2 updated for almost 2 years now. I would argue that the number of changes made to TF2 in that time are far more than the differences between L4D1 and 2, but that's for another post perhaps.
I hope it continues, but I also hope they get inspiration for Portal 2 and HL2 Episode 3 too.