Natural Cave in Gunung Mulu National Park (Borneo)
The things that you see on the ceiling, that look like pipes, are tree roots.
The mouth of this cave is located a few hundred meters North-East of the Clearwater cave entrance, and can be reached by an unmarked and faint jungle trail.
It is part of the Clearwater cave system, but it is one of the caves that tourists can visit officially, so go at your own risks!
I found it myself while scouting for photos (no-one told me about this cave). The cave is horizontal and I went in pretty far in by myself (with a headlight), up to the point where it would have been unreasonably risky to go further alone because of the slippery rock floor, dangerous water-filled wells and deep pits.
There were a few footsteps so I was certainly not the first one in this cave, but it is not often visited. I believe that it might connects to the Clearwater underground river.
Based on the cave map, it could be "Link Cave" or "Goldwater Cave", but local guides Ipoi and Roland told me that they call it "Turtle Cave".
This is a 69 sec exposure on tripod.