Birastrop

Birastrops, also spelled Birostrop, (PROSE: Scratchman) were a race of short insectoid beings. They had six spindly arms and a chitinous carapace which they could shed at will. Birastrop morality allowed killing for medical research. (PROSE: Where the Heart Is)

Birastrop lungs were capabled of safely breathing in cyanide. Dr Mehendri Solon obtained Birastrop lungs and put them in Morbius's new body, (TV: The Brain of Morbius) along with a Birastrop posterior. (PROSE: Mehendri Solon)

When Scratchman summoned an army of creatures from the Fourth Doctor's memories, the scarecrow replica of the Third Doctor recognised a Birostrop among them, believing they had gone extinct. (PROSE: Scratchman)