Shisno is a term that is first mentioned by Aliens, supposedly refer to humans as in a prejudicial manner. Gamma has stated that a Shisno is an alien term, pronounced "Shiz-no", which refers to the excrement of a foul creature's defecation. Shisno's are considered almost universally repulsive, partly due to the fact that their excrement produces its own excrement following initial defecation. It is most commonly used by Aliens as a racial slur for humans, demonstrating the animosity of the two species.
The term is brought up again in The Shisno Paradox. Huggins refers to the term Shisno as someone who has fallen under the influence of Chrovos and has been corrupted by time travel into fulfilling their dreams and working as one of the Agents of Chrovos. Huggins cites Doc as a Shisno due to his corruption by his O'Malley persona, while Grif is not, because although at first he solely wants to invent pizza, he eventually gives up his dreams and grants the time machine to Doc. In "A Sitch in Time", Genkins asks Chrovos about the duality of the term, to which she replies that the Great Prophecy implied humans would destroy the universe, "and the Fates are, I guess racists?"