Updated- end of thread,something in the black tank.

Ugly job!

But it needs to come out. Not good leaving it.

I would try to fish it out, either from the toilet on top (remove the toilet itself first), or from the waste valve side. Your specific plumbing will determine which is more practical. You could try renting a sewer vision system, so you can see into the tank. Then use a wire with a hook to snag it and drag it out. Maybe use the bore scope from one end while fishing from the other.