re: A captured comet or a big leftover chunk from the rings?
Or a few leftover chunks of combined icy rubble as Hyperion's density is low and seems to have voids in the interior. Is it being pulled apart with the help of Titan or is it in the stage of contracting from its own gravity?
If it is a comet, it's a dead one. No sign of spikes from outburst. It also shows a lot of craters.