The running beastworm gets its name from the way it attacks prey. When walking, it drags its tail behind itself, much like the beastworm. However, when it attacks a plent, its tail comes off the ground and it dashes towards its target. Its internal vibration-sensing organ has split into two different tasks. One functions like our inner ears, allowing it to balance better, though still not well enough to walk with its tail up. The other has formed into a primitive ear. It has a narrow canal (right between the front of the main carapace and the skin) leading to the outside air, allowing it to "hear" vibrations in the air (sound). Its internal support structure has increased in strength, necessary for running, and its former shells have almost completely lost their hardness, with the exception of the tip of the feet and the tip of the tail. Its olfactory organs have completely separated from the mouth, allowing it to smell much more efficiently. Some of the smell-sensing cells have remained in the mouth, giving it a sense of taste. It now hunts plents however it can catch them, though it prefers to catch them on their airhole, because they die much quicker. Its microlungs have also increased in size, especially the ones in places where it is most effective to have them. They are, however, still too small to see.
Artwork by OviraptorFan