Two years ago, Mark Rober was an engineer at NASA’s Jet Propulsion Laboratory in Pasadena, California, part of a team that worked on the Curiosity rover. For Halloween, he strapped an iPad to his chest and another to his back. Then he turned them on and used the devices’ cameras and screens to make it appear as if he had a gaping hole in the middle of his torso. (Photo By Mark Rober)

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)

(L-R) Leigh-Anne Pinnock, Jesy Nelson, Perrie Edwards and Jade Thirlwall of Little Mix attend the KISS FM Haunted House Party at SSE Arena on October 29, 2015 in London, England. (Photo by Dave J. Hogan/Dave J. Hogan/Getty Images)

A dog dressed in a costume as Greta Thunberg attends the Tompkins Square Halloween Dog Parade in Manhattan in New York City on October 20, 2019. (Photo by Johannes Eisele/AFP Photo)

David Nickerson, 28, competes dressed as artist Bob Ross, during the ZJ Boarding House Halloween Surf Contest in Santa Monica, California October 26, 2013. (Photo by Lucy Nicholson/Reuters)

Meatball, a bulldog, poses in a tuxedo at the Tompkins Square Halloween Dog Parade on October 20, 2012 in New York City. Hundreds of dog owners festooned their pets for the annual event, the largest of its kind in the United States. (Photo by John Moore)

A dog dressed as UPS worker is seen during the 28th Annual Tompkins Square Halloween Dog Parade at East River Park Amphitheater in New York on October 28, 2018. (Photo by Gordon Donovan/Yahoo News)

Dozens of people practice martial arts before the regional Government's headquarters in Barcelona, Spain, 27 July 2020, as a protest against the closure of gyms and martial arts centers in the region imposed by the Catalan Government due to a surge in coronavirus cases. (Photo by Enric Fontcuberta/EPA/EFE)