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 participant wearing a costume and make-up attends a Halloween parade at Walibi park in Wavre, Belgium, October 25, 2019. (Photo by Yves Herman/Reuters)

Revellers take part in a zombie parade to celebrate Halloween in Vina del Mar, October 31, 2015. (Photo by Rodrigo Garrido/Reuters)

Women dressed as nuns pose for pictures during Halloween celebrations in the Shibuya district in Tokyo, Japan October 31, 2015. (Photo by Thomas Peter/Reuters)

A worker works on a “Transformers” replica on the outskirts of Shanghai, June 18, 2014. Li Lei, owner of a small factory, uses his spare time and money to build “Transformers” replicas for rent or sale. The new Transformers movie, which is premiering later this month, has brought the factory many new orders, according to Li. (Photo by Aly Song/Reuters)

Mike Branch helps customers shop for a Halloween masks at Fantasy Costumes on October 28, 2011 in Chicago, Illinois. The store, which had long lines at the registers at 4 AM this morning, is open around the clock through Halloween to help keep up with customer demand. Retailers nationwide are expecting record sales for Halloween merchandise this year with shoppers spending close to $7 billion dollars to celebrate the holiday. (Photo by Scott Olson/Getty Images)

Angele Blank, right, and Virginia Promeyrat wait for the start of the Greenwich Village Halloween Parade, Saturday October 31, 2015, in New York. (Photo by Tina Fineberg/AP Photo)