In this episode...spiders! Whether you love them or are creeped out by them, you can't deny they're fascinating creatures. But did you know they're smart, too? Nick introduces us to a species of sheet-web spider that has developed a very interesting trick to lure prey, one that indicates a more sophisticated level of intelligence than we thought. Then, Dave takes us on a journey to the center of the galaxy to explore a bizarre realm of ionized gas and dark matter. At the middle of it all sits...