Plumbers: Any Ideas on what this is?

[M3]

I am a home inspector, and saw this in the basement floor of a 1920's home. I've never seen anything like it before, but guessing it is some old plumbing fixture or portion thereof... I posted it to my association forum and someone thought it may be an old bell trap improperly installed...?

I'm just trying to give my client some good information, and wondering if one of the forum plumbers can help identify it.

Thank you.

 

[Smooky]

Maybe it is an old cast iron shower drain with an inverted cup covering the drain opening.

 

[Sponsor]

 

[Reach4]

Inverted dog dish?

 

[Dana]

Looks like it might be an old floor-drain backflow preventer that somebody installed as a retrofit, probably after a rainstorm or flood backed up and flooded the basement with stinky stuff, but without actually breaking out the slab to install it properly, flush with the concrete(?). They came/come in a number of different looks. It's a bit tough to say without being on site to poke at it. If you push down on the center is it spring loaded- does it open up?

(I'm not a real plumber, never had a plumbing license, but I know which end of the plunger is the business end... )

 

[M3]

It's rigid, But may be that way because the entire floor was heavily painted...
Thanks for the feedback!