Theoretical Monsters: A Credibility Test was a book used in UNISYC troop training. It concerned the credibility of various aliens. There was a copy of this book in a UN building in Geneva in 1996. It listed the Cybermen, the Xxxxxxxxxlanthi (mind-chewers from the Fifth Universe), Gell Guards and the Kalekani (which used a terraforming virus on biospheres to replace all land with flats and slopes of green, On Earth it's called "golf".) (PROSE: Interference - Book One)