“Joey”, a dwarf Siamese rabbit, is dressed as Batman's sidekick Robin at a Halloween dog costume parade and contest in Long Beach, California, October 28, 2012. (Photo by Robyn Beck/AFP Pfoto)

Model Heide Lindgren attends Heidi Klum's 12th annual Halloween party at the PH-D Rooftop Lounge at Dream Downtown on October 31, 2011 in New York City. (Photo by Jemal Countess/Getty Images)

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)

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)

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)

Arachnids category 3rd place: dancing spider by Raed Ammari. Male jumping spiders (in this case a Phidippus insignarius) perform a courtship dance in which they almost form a heart shape with their legs. This one was shot in Colorado. (Photo by Raed Ammari/Luminar Bug Photographer of the Year 2020)

An unexpected side-effect of the flooding in parts of Pakistan has been that millions of spiders climbed up into the trees to escape the rising flood waters. Because of the scale of the flooding and the fact that the water has taken so long to recede, many trees have become cocooned in spiders’ webs.