Yes, a hollowing tool. The cutter does look to be angled slightly so it will give more of a sheer cut. I do not recognize any brand like it, and it could be home made. The vertical handle is for resisting torque as you reach out. If the cutter is in line with the square shaft, there should not be any torque. If it is off to the side a bit like in the pictures, then there will be some torque.
robo hippy