He sits there looking evil whenever an Evil Tweet is posted.
An Evil Tweet is the first 140 characters (or 25 words, if you don't care to count to 140) of an author's book or story. Your job is to continue the story (in the comment trail), bringing it to a conclusion, without exceeding your own limit of 140 characters (or 25 words).
You may also email your own Evil Tweet to email@example.com. Put "Evil Tweet" in the subject line.