Team Fortress 2 is celebrating its eighth (!) Halloween this year, and new events and items went live a few hours ago. Valve may be feeling a little pressure from Overwatch, because it looks like there's more new stuff available this time than in years past. Sadly, there's no new comic, but all of the new and old Halloween content will be active from now through November 9, 2016.
Three new Halloween-themed maps: Brimstone, Pit of Death, and Maple Ridge Event. The latter is a holiday decorated version of the regular Maple Ridge King of the Hill map.
Bumper car taunts for every class. Called the Victory Lap, these taunts are based on the 2014 TF2 Halloween event that featured a bumper car race in between the fighting.
Magic wand taunts for every class. These are called Second-rate Sorcery, because whatever spell the mercs are trying to cast doesn't work.
New crates and keys are a given, and during the event, opening any crates grants double the chance of a cosmetic item inside having an unusual effect (usually a glow or particle effect that surrounds the character) applied to it. Any item with an unusual effect opened during the event will be a Halloween 2016 unusual effect specifically, and presumably those will be unavailable after the event's conclusion.
New costume items include a chicken hat for scout, Hawaiian shirt for Heavy, and a bare-chest option for the Medic. There are several all-class items as well, including a cute knit bat hat. Try saying that a few times in a row.
Anyone who skipped last year's event will receive a Soul Gargoyle that tracks how many other players you kill in Halloween maps. It also unlocks Merasmissions, quests you can do to earn a classic Halloween item while the event is active.
It's amazing to look back and see how much extra stuff has gone into this game since its release. I'm not sure this is enough to pull me away from trying to get Mercy's Witch skin in Overwatch, though.