The term 'Riverside Romper' is a type of otter, specifically the North American river otter. It is a semi-aquatic mammal that lives in rivers, streams, and wetlands. The North American river otter is known for its playful behavior and is often seen sliding down mud banks or playing in the water. It is also an important part of the ecosystem, helping to keep the water clean by eating fish, frogs, and other aquatic animals.