Paleontologists in Arizona have finally figured out what animal made a set of 260 million year-old fossilized footprints. The fossilized imprints were discovered by paleontologist Raymond M. Alf in the Painted and Mojave deserts in 1968, and have been on display at the museum that bears his name in Arizona ever since. Now, after 46 years of experiments, experts are ready to say what kind of animal made the footprints. While the footprints appear to a layperson as if they were made by an animal with four toes, it turns out the footprints were made by a prehistoric spider crawling across wet sand. Yes, a 260 million year-old spider.