Conrad Bennish, Junior (played by Jason Gaffney) of Earth Prime is a University of California student in the same class in which Quinn Mallory is a student, which was taught by Professor Maximillian Arturo, in 1994. Arturo finds him brilliant but obnoxious. Quinn and Bennish are friends. Bennish has an interest in drugs and bombs. When the FBI showed up to question him about the disappearance of the Sliders, he said, "If this is about the bong I just bought, I thought it was a plant-holder, honest!" He dresses in a stereotypically "hippie" fashion, wearing long hair and sunglasses.
An alternate Conrad Bennish from "Summer of Love" has short hair, and identifies himself as President of Young Republicans For the War. He gave Quinn and Professor Arturo literature in support of the war that was taking place at the time on that alternate Earth between the democratic South Australia (backed by the United States) and the communist North Australia (backed by the Soviet Union).
A version of Bennish is seen in "Last Days," where it seems his genius may be unchecked, and a danger to his particular Earth. He is also trying to create the "failed" atomic bomb, which that Earth's Albert Einstein purposely sabotaged. With Professor Arturo's help, he builds one, and successfully launches it against the asteroid set on a collision course with the Earth.
The character only appeared once in the second season (and for the last time) in the episode "Invasion," though he is never named or credited as Bennish. Here, he is a prisoner of the Kromaggs, eyeless as a result.