I have an older bathtub with a plunger drain setup like this unfortunately, the drain opening is not an open drainpipe (it's some kind of closed stopper valve) so i can't try to do anything through there.
30+ Something Stuck In Bathtub Drain
Pictures. Something stuck in my bathtub drain? If you don't have any luck, use a toilet auger.
Help! Very stuck bathtub drain screw. : HomeImprovement from i.imgur.com
Some manufacturers refer to the drain flange as a drain body or drain basket. If the water drains out, repeat the process above and lower the plunger a little bit. If so, and you have used the tub, then water draining from the tub may have already flushed it.
Sometimes, these items gather and form a puddle of gunk that sticks to the pipes and the drain, causing an unsightly odor if not removed.
If the water drains out, repeat the process above and lower the plunger a little bit. Loosen the hose clamp from the tub. Identify your drain stopper before removing it. They gradually slow down, day after you know you really have to do something when you're taking shower but your feet and ankles slip it into the drain hole (which usually has some kind of strainer basket necessitating a small be careful not to yank on the wire if it gets stuck;