Yesterday I found a brain. Looked like an adult brain, but was very well preserved. Almost unused (though traces of alcohol abuse were clearly noticeable). Certainly had not run on full load often.
I found it on a server running an achievement map. I asked if somebody was missing this brain, but nobody answered. In retrospect the question was misleading anyhow. Because evidently nobody was missing anything. Certainly not other players with tons of spam, while standing in front of a resupply cabinet. Or running around aimlessly firing and bashing at other people in a headless chicken-like manner.
Whatever these people were doing, it had very little to do with getting achievements (though in all fairness I know there are a few achievements which require senseless killing). Also it was clearly out of the question that people would help each other getting some of the more complex achievements (unless you count a player deciding that all other players had silently volunteered to help him by letting him kill them).
A few of those fine gentlemen even tried to bring some good humour into the situation by either starting to spam constantly while standing in front of the resupply cabinet or by going engy and building a sentry overseeing the map’s spawn area which would consequently shut down the other team. A fine achievement indeed.
In the end I came to the conclusion that the brain I found was probably an alien artifact. It clearly did not originate from the people playing this achievement map. Those people would have mistaken a brain for a hat.