That's the "probe and drogue". The complicated thing is the probe, the conical thing is the drogue.
The docking between the Apollo command and lunar modules employed the
use of a "probe and drogue" system. The probe was mounted in the
docking tunnel of the command module, while the conical drogue was
mounted in the docking tunnel of the lunar module.
The CM would extend its probe and approach the lunar module. The cone
of the drogue would guide the command module until it was properly
centered, and the capture latches on the tip of the probe would
engage, effecting "capture." The probe would then be retracted until
the docking tunnels of the two spacecraft met, and the 12 docking
latches on the command module would engage the LM's docking tunnel,
effecting a "hard dock."
Once hard dock was achieved, the probe was collapsed, removed from the
docking tunnel, and stowed. This allowed access to the LM's drogue,
which was similarly removed and stowed, allowing access to the LM's
As far as where the picture is taken, it appears to be in the lower equipment bay of the Command Module. There's a cool 3D model of the Command Module you can fly through here. I couldn't totally control the eyepoint (could be pilot error) but I got pretty close. I screen-shotted the model and annotated three prominent features with red arrows. Then I pasted in one of the images from the combo shot in the question and annotated the same features with green arrows.