An example of a "Derp".
The Cox Derp Counter was created in late 2013 by users Buffalo_Bob and Buugar. The Counter records all of Jesse's misdoings and failures caught while on most livestreams. While starting off merely as a joke, it has become a common and welcome sight during his livestreams (at least with the viewers).
In December 2014, the counter celebrated it's unofficial 1st birthday during Cox's Shadow of Mordor Wrap-up stream.
The full list of Derps can be found Here.
The unofficial 1-Year celebratory image