Greater Herbivorous Plent
These nifty creatures are the descendants of the herbivorous plents. While physically they don't appear to have changed much, other than in size (they are now the size of small rabbits, about 30 cm long), they have actually made some major evolutionary steps. First, they have developed a primitive nervous system. This allows them to "know" when a butt-plug worm is in their air-hole. They have not, however, developed any reflexes yet, so they are forced to just run around stupidly until they suffocate. Other changes include: a more effective digestive system, allowing them to chew; their feet now end in pads, to more effectively distribute weight; and their sight organ has developed into two distinct regions, and has increased in overall function.
Artwork by Oviraptorfan