Residents in Goulburn, South Australia, had a horrifying shock when thousands of baby spiders rained down from the sky. The town was invaded by the arachnids as homes and gardens were reportedly covered with the spiders and mounds of their silky threads.The phenomenon of spiders falling from the sky - commonly known as "spider rain" - is not uncommon across parts of Australia.It is caused by spiders climbing to the highest heights that they possibly can before they use their web silk as tiny parachutes and leap off.The silk catches on the breeze and carries the spider wherever it wants to go. Although this is happening all the time it is fairly rare for millions of spiders to do it at the same time and land in the same place.Bad luck for the people of Goulburn. ..