ArenaNet has updated the official Guild Wars 2 site with news about this year's Halloween festivities in game. It's great news for everyone.
“Our Halloween celebrations are in full swing, costume brawls are aplenty and the Shadow of the Mad King is falling across Tyria. Because we are as excited as you are, we will add another opportunity for you to get shiny Halloween goodies.
You will be glad to hear that we are adding recipes to the Mystic Forge that will allow you to throw stuff you get from the Black Lion Chests into it to get a special Halloween chest (no key needed for this one). These chests will include Halloween specific loot and give you a second chance to get one of the terrifying, rare Halloween skins. Here is the recipe we will add:
You need 1 Candy Corn, 6 Mystery Tonics, 1 Boost (any), 1 Boost (any) to get a Mad King Chest.
We hope you like this gruesome addition, we will let you know immediately when they will be in the game – enjoy the celebrations!”
Source: GW 2 Site