This was growing on an oak tree stump. Is it Oak mazegill? It was pretty large and kinda thick.
Possibly Nemertea. Water sample collected recently, likely at at Muller pond.
A large network of trails and burrows estimated at about 4in in width that lead to and from the cluster of trees. They appeared freshly used and well worn but I did not find any signs of scat, fur, shedding, or feathers.