Pokémon Pokopia's Halloween event has you startling Pokémon for candy
Pumpkaboo's Candy runs from October 17 to November 1 in Pokémon Pokopia, adding Pumpkaboo and Gourgeist and a trick mechanic where you disguise yourself as furniture to spook townsfolk into handing over sweets.

Pokémon Pokopia is getting its first Halloween event. Pumpkaboo's Candy opens on October 17 at 5:00am local time and runs until 4:59am on November 1, adding Pumpkaboo and its evolution Gourgeist to the game.
How the trick works
Pokopia already lets you transform, and the event turns that into a prank. Head into town, disguise yourself as a piece of furniture or a decoration, wait for a Pokémon to wander over, and startle it - the payoff is Pumpkin Candy, the event's currency.
Candy goes back to the Pokémon Center and comes out as furniture and items themed on a midnight festival. Build a habitat out of that furniture and you can befriend Pumpkaboo itself, which is the loop Pokopia has always run: the decorating is the progression.
Two requirements are worth knowing before October 17. You need at least one Pokémon Center built to take part, and your game has to be on version 2.0.1 - the patch that went out this week, following August's larger 2.0.0 update. Talking to the Pumpkaboo standing outside the Pokémon Center is what starts the event.
What 2.0.1 fixed
The required patch is a bug-fix pass rather than a content drop. It stops Ho-Oh and Lugia repeatedly falling and reappearing under certain conditions, fixes Pokémon that could not be found through the Pokédex search, sorts out a Move Kit that would not get picked up, quiets some repeating sound effects and closes off a freeze.
Why it matters
Pokopia launched in March as a decorating game with Pokémon in it, and seasonal events are the obvious way to keep that kind of game turning over. This one is small - two Pokémon and a furniture set - but it is the first sign that Pokopia is being treated as something to return to rather than finish, and the version requirement suggests events are now tied to the patch cycle.
Why it matters
Pokopia's first seasonal event is the clearest signal yet that Nintendo intends to keep updating it, and it ties participation to a specific game version - which suggests a regular event cadence rather than a one-off.