Bonobo apes, primates unique to Congo and humankind's closest relative, groom one another at a sanctuary just outside the capital Kinshasa, Congo on October 31, 2006. (Photo by Finbarr O'Reilly/Reuters)

A cosplayer poses for photographs at the 2015 Comic Fiesta event in Kuala Lumpur, Malaysia, October 31, 2015. (Photo by Olivia Harris/Reuters)

The 2016 Greenwich Village Halloween parade, October 31, 2016 in the Manhattan borough of New York City. (Photo by Anthony Causi)

Members of the Beltane Fire Society take part in Samhuinn Fire Festival on October 31, 2023 in Edinburgh, Scotland. Once celebrated from October 31 to November 1 by ancient Celts, Samhain, pronounced “SOW-in” or “SAH-win”, marked the shift from the brighter to the darker half of the year and was seen as a time when the boundary between the physical and spirit worlds was thought to weaken, influencing the development of contemporary Halloween customs. (Photo by Murdo MacLeod/The Guardian)

A young man performs a wheelie on his bicycle during a stunt show in the Petare neighborhood of Caracas, Venezuela, on Sunday, October 31, 2021. (Photo by Pedro Ramses Mattey/Anadolu Agency via Getty Images)

A participant in costume and make-up poses for a photo during a Halloween parade at Walibi park in Wavre, Belgium, October 31, 2018. (Photo by Yves Herman/Reuters)

A child dressed as a cat takes part in the Children's Halloween day parade at Washington Square Park in the Manhattan borough of New York October 31, 2015. (Photo by Carlo Allegri/Reuters)

A dog dressed in a costume takes part in the Pet's Halloween Day parade at El Olivar Park in San Isidro, Lima, October 31, 2015. (Photo by Mariana Bazo/Reuters)