Pting

The Pting were a species that existed in the 67th century.

Biology
Pting were a tiny species that fed off energy in order to survive. They were a vicious species, but were strictly non-carnivorous and didn't consume anything with organic matter. The Pting were able to consume any material that could incarcerate or threaten them, including the Thirteenth Doctor's sonic screwdriver making imprisoning them impossible and confining them to small areas dissuaded. They were believed to have been unkillable and could survive 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 an vid-briefing that was available on the Tsuranga. It had been allocated the threat level, Chalice, which was the worst one.

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.

Another Pting sneaked aboard the Tsuranga in an attempt to consume its anti-matter power core only for the Thirteenth Doctor to stop them. Before this particular Pting got hold of the bomb, it tried to eat it's way through the ship. (TV: The Tsuranga Conundrum)

Behind the Scenes
The Pting largely acts similar to a Gremlin in the story, "sabatoging" a craft. It also bears similarity to the Disney character Stitch for its eating habits, rather quick speed, and being cute in appearance despite occasionally showing viciousness.

The poison-to-touch bit about its biology was an extra annoyance for the Doctor that got thrown in to make the Pting harder to get rid off.