I think this is Phidippus princeps, but it’s a highly variable species and I didn’t feel like hacking it apart to examine genitalia. Plus I don’t know how to key out spider genitalia at all, so it would have been a senseless thing to do. But it was definitely capable of jumping: leaped onto my lens twice, which is always a bit unnerving. They are harmless, but when you are habituated to seeing them through a macro lens, the subconscious brain tags them as massive predators. I survived. This was one of three spiders I photographed within a small area in Swarthmore, PA, a few days ago.
Found this clump of fluff a few days ago and initially wasn’t sure what it was. I’d assumed it was some sort of a gall, but when displayed on a big monitor I could see there were legs sticking out. Pretty sure it’s a spider parasitized by a cordyceps fungus. I’m guessing Torrubiella leiopus. But if I’m wrong about it being a spider underneath, I’ll retract that guess. Sort of looks like Sideshow Bob on The Simpsons.