Mad King Thorn

Mad King Thorn (the Mad King) appears every three hours starting at noon (PST in US, GMT in Europe) in Lion's Arch, in the mushroom circle.

When he arrives, he starts commanding people. If you do what he want - usually by emoting - you will receive different Halloween treats. At the end of the game he will give everyone a Pumpkin Head. The game lasts approximately 20 minutes and includes jokes, commands, rock-paper-scissors games and a "Simon Says"-like game at the end.

Below are some screenshots of his visits to Lion's Arch: 