Because nightmares live underwater too. No but seriously, these spiders are friggin’ awesome! These spiders use their webs to trap air bubbles and use them to breathe underwater, kind of like gills in that the bubble will extract oxygen from the water (by diffusion) when concentrations are low. The silvery appearance comes from the bubbles surrounding the spider because of hairs that trap air. Since they rely on cutaneous respiration to breathe, the bubble layer can act like a space suit even if it is only around certain parts of the abdomen. They only need to resurface when nitrogen levels in the bubble drop, this causes the bubble to collapse, so replenishing the nitrogen prevents that. During times of winter when the lake may freeze over, they simply gather enough air to the bottom of the lake to last a few weeks.