As spirits stir and the undead rise from ancestral tombs, stalwart adventurers will be tasked with special activities that will reward them with gruesome goodies, terrifying treasures, and awesome achievements. - TESOnline
Despite the knowledge that seasons, dates, and holidays are meant to play special parts in the Elder Scrolls Online lore, ZeniMax haven't done much with the idea. This year, however, their hosting a special Halloween event: the Witches Festival.
Players can collect a free item called the "Crow Caller" from the Crown Store to activate special quests and other events. This limited-time item will allow players to transform themselves into an Undead for a limited amount of time and can be used as many times as the player wishes before the beginning of November. Being Undead allows the players to gain extra benefits when defeating bosses and open special skulls chuck-full of loot.