Polterkitty

Polterkitty is Hellen Gravely's ghostly cat which appears as a recurring boss in Luigi's Mansion 3. Her behavior is similar to that of Polterpup in Luigi's Mansion: Dark Moon.

History
Polterkitty is first seen in a cutscene after Luigi rescues Toad, where she is seen on Hellen Gravely's lap while she watches Luigi's progress. After Luigi retrieves an elevator button from Morty in the Paranormal Productions, Polterkitty steals the elevator button as soon as it is placed in the elevator. Luigi must use his Dark-Light Device to reveal Polterkitty's invisible footprints which lead to her location. After Luigi flashes Polterkitty with his Strobulb, she will transform into a monstrous panther-like form. Whenever Polterkitty takes this form, Luigi must face away from her in order to provoke an attack. When the ghostly feline is just about to attack (rearing up and spreading her forelimbs wide as her eyes flash pink), Luigi must quickly turn around and flash her with the Strobulb, stunning her long enough for him to vacuum her with the Poltergust G-00. Doing this the first time only pulls off one of Polterkitty's tails, and she then flees to the Garden Suites, where Luigi chases her to. After yanking off her other two tails, Polterkitty gives up the elevator button and returns to Hellen Gravely.

Polterkitty reappears after Luigi retrieves another elevator button from Johnny Deepend in the Fitness Center, once again stealing the button after it is placed in the elevator. This time, Polterpup helps Luigi track down Polterkitty, and together they hunt her down in the same way as before. Polterkitty has regrown the tails she had lost previously - she flees to The Spectral Catch after losing one of them, then moves to the Twisted Suites when she loses another. When Polterkitty is cornered for the third and final time, she attempts a fake-out of her own; as soon as Luigi turns to counter her attack, she quickly goes right behind him with another slash primed. If Luigi reacts to this in time to stun Polterkitty, he will have a chance to completely suck her into the Poltergust G-00, retrieving the elevator button she stole and putting an end to her mischief for good.

Upon confronting Hellen Gravely in the Master Suite, she specifically mentions Polterkitty's capture as one of her many grievances against Luigi prior to their battle.

In the Gallery, Polterkitty shares the same containment jar as Hellen Gravely, although she will not appear until Hellen is captured.