Harvestman, or Daddy Longlegs, is a small eight-legged animal related to the spiders. It lives in temperate and tropical regions. There are over 3,200 species, 200 of which are native to the United States. Unlike a spider, a harvestman has long, stiltlike legs and a segmented abdomen, and lacks silk glands. The legs each have seven joints, making them highly flexible and allowing the animal to run rapidly over leaves and grass.
As indicated above, this mob is smaller in size than the other spiders surrounding it, this is intentional and correct.