Looks like a christmas decoration.....a wreath or something
perhaps I am thinking of Saint Pats day....
the IRISH green,,, you know..
Just leave it in place and go get one of those OATEY
expandable PVC flanges that goes down into that 4 inch hole...
all ya got to do is put it in the hole and use an allen wrench
and tighten it down into place....
if it seems too high,
just take and break off that cast iron flange lip
they work great and keep me out of lots of combat situations..