Jack looked around to examine the rocks. The Doctor was right, this was new and manufactured. He touched a hand to the rock and felt the etched markings.

They advanced ahead and the water seemed colder the further they went. Whatever was drawing the heat? They were closing in on it.

He opened his mouth to say something but he was swiftly cut off by the Doctor suddenly disappearing from view.

"Doctor!" Jack called, looking down at the water to try and see what happened. He could see nothing though but the bright light and an indistinguishable shape. And so he took a deep breath and plunged under.

What he saw there, chilled him. A creature of some sort that seemed to be connected to the rock, a little as though it were part of it, and from it tentacles that stretched out and pulsed the electric shocks that spanned through the water. One tentacle however was dark, and that one hooked around the Doctor's leg as it pulled on him.

Jack swam to it and reached out, attempting to dislodge the hold as it wrapped around him. He tugged and pulled, but it wouldn't give.