The Jester (also known by the leetspeak handle th3j35t3r) is an unidentified computer vigilante who describes himself as a grey hat hacktivist. He claims to be responsible for attacks on WikiLeaks, 4chan, Iranian President Mahmoud Ahmadinejad, and Islamist websites. He claims to be acting out of American patriotism. The Jester uses a denial-of-service (DoS) tool known as "XerXeS", that he claims to have developed.