The guy who discovered this metallic object was stumped as to what it could be. It had a piece of rope running through it, though he wasn’t sure that the thing was there just to hold rope. So, he did what the rest of us should do: ask the internet.
And the internet was quick to provide him with answers. This thing is a pipe fitting, which consists of three parts—a tee, a nipple (lol), and a flange. You can mount the flange onto any surface with screws, and the tee portion will keep pipes in place at any orientation or angle.