Eight-meter-long centipedes and dragonflies with a meter-long wingspan are the realities of the Paleozoic era
During the Paleozoic Era (541–252 million years ago), there was enough atmospheric oxygen to support giant superbugs and insects. For example, the largest giant dragonfly had a wingspan of up to 28 inches (71 cm). The giant centipede could reach eight feet in length (8.5 meters), making it the largest known invertebrate in history.