Found this in a heavily wooded area of White Rock Lake. When you look close, it is very pretty with soft furry bristles and a bright pattern on the back that reminds me of aztec symbols. These are harmless. According to Wikipedia, they lay down strands of silk as they move over branches and then travel along them like tightrope walkers.
Forest Tent Caterpillar Hodges#7698 (Malacosoma disstria)