Unknown Object in main drain

[irgoodwin24]

Hello! I’m new here but I have an interesting problem.

Recently completed large basement build (4 months ago) Bathroom is below grade and pipes lead to ejector pump. The bathroom has had limited use, and just recently backed up. I had plumbers come out and try to clear the pipe with no luck. With a camera going through the clean out, we found this blockage. Immediate reaction is that it’s a test plug.

I have 2 questions:

1. Any ideas what this is?
2. Any ideas on how to get it out without jack hammering many feet of concrete? Its many feet below the finished floor.

Thanks!

 

[Geofd]

If it's a rubber test ball a cutting head on a snake should puncture it but you have to keep the ejector off until it's cleared if that's what it is