Burst

A Burst is a special move introduced in Luigi's Mansion 3 that can be performed by both Luigi and Gooigi. It can be performed by pressing and  simultaneously.

Usage
Bursts create a large gust of wind below the player, causing various effects.

Performing Burst will launch the player a bit into the air (they cannot perform any other action or move while Bursting). Objects in the vicinity will be pushed away and/or break. If ghosts get too close to the player, Burst can be used to throw them away. If a Slinker grabs the player, the burst is required to keep it off. The player can also use the Burst to dodge shockwaves from some boss ghosts e.g Amadeus Wolfgeist or Ug or the Boolossus battle in the ScareScraper.

The description for the burst in the E3 trailer states: "Sometimes ghosts may feel inclined to gang up on you, in such situations a Burst should do. The powerful air pressure released will blow away ghosts, and it's perfect for when you need a little air."