Megan Fox, Camila Cabello, More Stars Dress Up for Halloween Party at Chateau Marmont

The spookiest celebs brought controlled chaos to the Chateau Marmont ... with stars showing off their most creative costumes at the famous hotel's annual Halloween party.

Some of the biggest stars in H'wood pulled up to the big bash in elaborate costumes ... like Machine Gun Kelly and Megan Fox, who crushed an Anakin Skywalker and Padmé Amidala couple's costume.

Newly engaged stars Nina Dobrev and Shaun White dove into Batman's rogues gallery for their costume ... channeling Catwoman and the Riddler from the hit 1990s 'Batman' films.

Camila Cabello traded in the Playboy Mansion for the Chateau ... stunning in a Playboy Bunny ensemble that would make Hugh Hefner proud.

Sisters Halle and Chloe Bailey went as cartoon sleuths Daphne and Velma from 'Scooby-Doo' ... while Rebel Wilson and her new wife, Ramona Agruma, brought the Southern charm in cowboy getups.

Among the other celebs in attendance ... Rosalía, Charli XCX, Lori Harvey, Addison Rae, Emma Chamberlain, Chantel Jeffries, Natalia Bryant, Cher and more brought the horror to Kendall's bash.