From Press Release:
Starting today, Destiny 2’s Festival of the Lost free, in-game event is back through November 8. As is tradition, players will don spooky (and silly!) masks and collect treats by completing challenges in and around Haunted Sectors throughout the system. This year’s treats include the new Legendary Sniper Rifle Mechabre, the community-chosen Mech-themed armor ornament set, and additional cosmetics unlocked in the Festival of the Lost Event Card.
Event Card Rewards
The new Festival of the Lost Event Card introduces challenges as well as free and premium rewards for all players. Similar to the Solstice event last Season, players can use the Event Card to unlock new cosmetic items such as a new emote, ship, Exotic Ghost, and more.
Haunted Sectors
New this year is the Haunted Sector in the EDZ, where the ghoulish Cabal will attempt to trick you out of your treats 
. Guardians can explore the frightening Haunted Sector playlist, where players take on the Headless Ones in new and returning Haunted Sectors.
Mech-themed Armor Ornaments
Last year, the community voted on their Festival of the Lost costumes for the first time, and now they’ve done it again with #TeamMech. Now available in the Eververse store for Bright Dust or Silver, players can grab their Mech-themed armor to trick-or-treat around the system in style.
Bungie Rewards
The Headless One T-Shirt is available at the Bungie Store to Guardians who achieve the Bookworm 1 Triumph by unlocking 1/3 of the pages for Book of the Forgotten during the Festival of the Lost event. Also, the Ghost Writer Collectible Medallion Pin will be available for pre-order from the Bungie Store for players who complete the new in-game Seal and the title associated with it. The last day to unlock these rewards is at the end of the event on November 8.
While players can enjoy grabbing their candy and treats in Festival of the Lost, they can continue to hoard treasures in Season of Plunder, which continues until December 6.
