Metatraxi

Metatraxi were an insectoid species.

Biology
Metatraxi ate their own parents on hatching. (BNA: Down)

History
In 1989, Raine Creevy, the Seventh Doctor and Ace defeated the Metatraxi in the Kingdom of Sayf Udeen. (BFA: Crime of the Century)

The Vancouver was attacked by the Metatraxi while bringing food to Safenesthome. (BFA: Earth Aid)

The Krotons went to war with the Metatraxi, during which they devastated their homeworld. (EDA: Alien Bodies)

The Metatraxi were involved in conflicts with the Daleks. (DWM: Abslom Daak - Dalek Killer)

Behind the scenes
Originally, the Metatraxi were to be featured in Earth Aid, a TV script written by Ben Aaronovitch for the Seventh Doctor in the cancelled Season 27. In this story, they would have been seen to be forcing their enemies through all methods, particularly bargaining, to take a weapon, as a problem in their mental complex was that they could not harm un-armed opponents. They later appeared in the audio version of the same story which was produced by Big Finish Productions as part of their The Lost Stories range of audio stories.