Rhizodus was the largest freshwater fish that ever lived. It roamed the planet in the entirety of the Carboniferous period and was probably the apex predator of the freshwater ecosystems. It was almost 25 feet long and had fangs that were close to 9 inches in length. It usually ripped apart its prey rather than swallow it whole. It has been proposed that Rhizodus could lunge out of water like a crocodile to capture terrestrial prey.
Rhizodus is an AI controlled boss creature that lurks around the Grand River and Carnian Swamps. It does very high damage as well as the Bleed side effect. It is extremely aggressive and will not hesitate to attack any creature in the water.