Demonstrators in Hong Kong took to the streets in masks and colorful makeup, taking advantage of a truly ironic confluence of Halloween and a court challenge to Hong Kong’s recently enacted ban on face masks.

Masks have been a crucial aspect of the large protests that have engulfed Hong Kong for months. To shield themselves from police surveillance or tear gas, protesters have taken to covering their faces with gas masks and other face coverings. Challenges to the ban were heard in court today (Oct 31).

Mask-clad protestors focused their demonstration in Lan Kwai Fong, a popular party street packed with bars and restaurants that plays host every year to large celebrations on Halloween. Police responded by cordoning off the area and firing tear gas and pepper spray to break up the parties, and protests.

Photos show an array of the face coverings favored by protesters, including the ubiquitous Guy Fawkes masks, Joker makeup, and the face of Hong Kong chief executive Carrie Lam.

Reuters/Tyrone Siu Anti-government protesters wearing costumes march during Halloween in Lan Kwai Fong, in Hong Kong’s Central district on Oct. 31.

Reuters/Shannon Stapleton A protester in Joker makeup takes part in a Halloween march in Hong Kong on Oct. 31.

ANTHONY WALLACE/AFP via Getty Images A Halloween reveler walks past a line of policemen in the Lan Kwai Fong area.

ANTHONY WALLACE/AFP via Getty Images A line of policemen stop Halloween revelers in the Lan Kwai Fong area in Hong Kong on Oct. 31.

ANTHONY WALLACE/AFP via Getty Images People shout slogans in front of a line of policemen in the Lan Kwai Fong area during Halloween in Hong Kong.

AP Photo/Kin Cheung A person dressed as president Donald Trump waves an American flag as they stand on a street in Hong Kong on Oct. 31.

AP Photo/Kin Cheung A man in a Halloween costume walks past police officers in riot gear in Hong Kong on Oct. 31.