An Informational Illusion was an illusion that made you experience things as if you were there, but physical harm could not be done to you, as it was merely an illusion. There was one on the Starship Bistromath, and Slartibartfast used one to show Arthur Dent and Ford Prefect how the people of Krikkit discovered the universe and how they subsequently faced trial.
Several Krikkiters were shown within the Informational Illusion used by Slartibartfast, including the Krikkit judge Judiciary Pag. The ships Starship Titanic and Krikkit One, as well as Soolfinians and the planet Vod, also appeared.