Update: The event has now been confirmed by Nintendo and it starts 16:00 CEST on 19/10 until 16:00 CEST on 21/10, and you can pick a side from 05/10. It is a special Splatfest
Original post: Halloween is fast approaching and it looks as though Nintendo will be celebrating with a special event in the excellent Splatoon 2. The news was discovered by dataminer Ink Larry on Twitter and he has found a logo for Splatoon 2 Splatoween amongst other things. Nintendo will presumably announce the event fairly soon.
Thanks to darthwesker10 for the tip!