Pting
The Pting were a species capable of eating a variety of inorganic materials, but which subsisted off of energy.
Biology
Pting were a small bipedal species. Although vicious, they were strictly non-carnivorous and could not consume organic matter. They could consume, however, any inorganic material, including the Thirteenth Doctor's sonic screwdriver, which made it virtually impossible to contain or confine them. They were believed to have been un-killable and could live without oxygen. They were also deadly to the touch as they excreted poison. (TV: The Tsuranga Conundrum)
History
Many attempts to study the Pting had failed, as had all attempts to keep some in captivity. Nevertheless, by the 67th century, Item Seven Alpha Cubed of the Perils of the Constant Division was a vid-briefing that was available on the Tsuranga. It had been allocated the threat level, Chalice, the highest level.
Eve Cicero once encountered a Pting. It massacred her entire fleet and she learnt from the encounter that they kill relentlessly, a fact that she relayed to the Doctor when faced with another one. She also remarked that they could be stunned by a stazer.
Another Pting sneaked aboard the Tsuranga in an attempt to consume its anti-matter power core only for the Thirteenth Doctor to stop them. The Doctor removed a detonation device for this particular Pting to devour rather than the ship's core, subsequently ejecting the creature in to space. (TV: The Tsuranga Conundrum)