Polterkitty

Polterkitty is Hellen Gravely's pet cat, and a boss in Luigi's Mansion 3.

First Battle
After acquiring the button for the ninth floor from Morty and putting it in the elevator, Polterkitty steals it and runs off, forcing Luigi to track her down and retrieve it the hard way.

Second Battle
Polterkitty returns to cause Luigi more grief after he captures Johnny Deepend and receiving the 14th floor button. The good news is this time, Luigi has his Polterpup to help track down the ghostly feline.