UPDATE 5/10/18: Earlier this week, Nintendo announced that Splatoon 2 would be getting spooky this month with a special Splatoween Splatfest event - and, mere days later, the preliminary festivities are now underway.
Although the main Splatfest event is still two weeks away, kicking off at 3pm on Friday October 19th, eager revellers can now sign up to their team of choice - the selection inevitably being either trick or treat - via the booth in Inkopolis Square. Far more excitingly, however, Splatoon 2's free Hallowe'en gear is now yours for the taking too.
Four items are available - the Kyonshi Hat, Li'l Devil Horns, Hockey Mask, and Anglerfish Mask - and to add them to your wardrobe, you'll first need to be signed up to the Squid Research Lab feed on the Switch's new channel. Once done, you'll either receive - or can hunt out - the relevant announcement post, which includes a button that launches the game. Press it and you'll find your gear waiting in a cardboard box in Inkopolis Square.
Nintendo hasn't specified how long players have got to claim their freebies, but I'd imagine they'll remain available until the start of Splatoween, at the very least.
ORIGINAL STORY 3/10/18: Nintendo has announced that it's getting into the spirit of the spooky season with a special Hallowe'en-themed Splatfest event, coming to Splatoon 2 soon.
Catchily known as Splatoween, Nintendo's celebratory global Splatfest will run from 3pm, Friday October 19th to 3pm October 21st, and sees the ever-fashionable Inkopolis Square on the receiving end of a major seasonal makeover. The city's bustling hub will be draped in ghoulish bunting, and given an extra flourish with an appropriately nauseating orange and slime green colour scheme.
The macabre merriment will also carry over into Splatoween's stage roster, with Moray Towers, Starfish Mainstage, and Musselforge Fitness all looking a touch more spine-tingling that normal in the screenshots accompanying Nintendo's Splatfest announcement in Japan.
Nintendo will be completing the spooky aesthetic by giving players access to a pleasing selection of Halloween costumes - including demon horns and a Jason-Vorhees-inspired hockey mask - via the Splatoon 2 feed (also known as the Squid Research Lab Bulletin) in the Switch's news channel. Now is probably a good time to subscribe if you haven't already.
According to Nintendo's Japanese Twitter account, the not-entirely-unexpected theme for this seasonal Splatfest will be Trick versus Treat. Participating squid can sign up to their team of choice starting this Friday, October 5th.