If you want to suck up ghosts with friends you're going to need to unlock Luigi's Mansion 3 online multiplayer and head to the scarescraper. But the option isn't available as soon as you start the game, you'll need to earn your keep in the story mode first.
It isn't too far to go to unlock online multiplayer in Luigi's Mansion 3, and though local multiplayer is available right away to play with up to eight people on a single console, these are mostly just minigames. Head on up the spooky tower next to the hotel by unlocking the Scarescraper and head online.
How to unlock online multiplayer in Luigi's Mansion 3
The prologue of Luigi's Mansion 3 is pretty short, so run through Luigi and his pals getting tricked into checking in at a ghostly hotel, and then escape the unleashed King Boo. After this the game begins properly, however you'll still only have your flashlight and Poltergust, what you need to unlock online multiplayer in Luigi's Mansion 3 is Gooigi, your new gloopy friend.
To unlock Gooigi you need to carry on through the story and rescue E. Gadd, he'll ask you to retrieve a briefcase from his room. Once you've done that, by defeating a thieving maid ghost using your Poltergust's plungers, take the briefcase back to E. Gadd's lab in the parking garage and he'll introduce you to Gooigi. Familiarize yourself with the controls, you'll be needing him a lot this game, and then you'll be introduced to the online multiplayer ScareScraper. You can then choose to begin the ScareScraper from the menu in E. Gadd's lab, alongside local multiplayer.
Online multiplayer in Luigi's Mansion 3 allows you to play with up to four friends, two on each console with two Luigis and two Gooigis. Or you can each play Luigi and control Gooigi as normal. The ScareScraper is a tall building where you must fight increasingly difficult ghosts on every floor, so you and your friend had better be up to the challenge!
Now that you know how to unlock online multiplayer in Luigi's Mansion 3 you might also want to know where to find all the secret Boos hidden around the hotel?