Pting are tiny, violent creatures that survive on energy and devour all non-organic material, making them impossible to keep captive. Their skin is also toxic to the touch and they can survive without oxygen in the vacuum of space.
The Doctor, Ryan, Yaz and Graham encountered a Pting when they found themselves injured and stranded on board a Tsurangan hospital spaceship in a far-flung galaxy. The little alien had managed to sneak on-board and was hell bent on consuming everything, including the anti-matter drive which powered the ship.
The Doctor and her friends along with the crew and patients on board the ship banded together to survive against this deadly - and unusual – creature. The Pting was eventually outwitted when the Doctor removed the detonation device from within the ship and gave it to the Pting to consume. It exploded inside the Pting and as it absorbed the energy, the Doctor ejected it out of the spaceship and into space, saving everyone aboard the ship.