Clearing a clogged tub
Finally got a plumber out.  Apparently the device should have been removed when the previous owner redid the bathroom, so now it's sort of "stuck" or a part of the tub.  It can be removed, but will be fairly costly to remove.  The plumber actually broke his snake trying to get down to the clog, so it wasn't just me having problems.  Fortunately, the tub seems to be draining a bit better these days.