ScreamPark is a multiplayer mode in Luigi's Mansion 3 similar to ScareScraper. It is available from the start of the game and can be played before the player even begins Story Mode. ScreamPark can be accessed at any time from the title screen or in Professor E. Gadd's lab. Its name is a play on the term "theme park".
Like ScareScraper, ScreamPark can be played with up to eight players, divided into two teams: a team of Luigis and a team of Gooigis. Up to four players can be on each team. The colors for the different Luigis and Gooigis are green, blue, orange, and pink.
There are three game modes in ScreamPark: Coin Floating, Ghost Hunt, and Cannon Barrage. In Coin Floating mode, players must collect coins in a pool while dodging falling explosives. In Ghost Hunt mode, players must catch ghosts in a graveyard to earn points. In Cannon Barrage mode, players must fire cannonballs at targets to earn points. In every game mode, the player or team with the most coins or points at the end wins.
In Coin Floating mode, players must collect falling coins in a hotel pool while avoiding falling explosives. Each Luigi and Gooigi is in a floaty which is controlled with Poltergust G-00 controls. If one of their floaties hits a spike ball or bomb, it pops and they are thrown out of the pool, dropping all their coins into the water. They must then blow up another one by pressing repeatedly to get back in. The Luigis' floaties look like swans, while the Gooigis' floaties look like dragons. The player or team with the most coins at the end wins. Each round lasts two minutes.
Occasionally, a Super Star appears and bounces around in the pool. If a Luigi or Gooigi grabs it, they become temporarily invincible and are safe from explosives. While invincible, players can also ram into players on the other team to pop their floaties to send them out of the pool.
In Ghost Hunt mode, players must catch ghosts in a graveyard to earn points. Goobs, Hammers, and Golden Goobs appear and can be captured. Goobs are worth one point each, Golden Goobs are worth three points, and Hammers are worth fifteen points. Golden Goobs can be found in glowing gravestones. The player or team with the most points at the end wins. Each round lasts two minutes.
Usually, the gates are locked, but they will unlock automatically after a while or if someone finds the hidden key in one of the gravestones. When the gates are unlocked, more ghosts start appearing, including Hammers.
In Cannon Barrage mode, players fire cannonballs at targets to earn points. Regular targets are worth one point each, while golden targets are worth three points. The player or team with the most points at the end wins. Each round lasts three minutes.
Players must load cannonballs onto their team's cannon by vacuuming them up, placing them into the cannon, then pressing near the cannon to fire the cannonball at a target in time. Rare golden targets sometimes appear and move behind regular targets, making them harder to hit. Sometimes Goobs will appear holding cannonballs. Players can also steal cannonballs from other players by using a Suction Shot.