I can imagine, if Krull were someone's homebrew game, it went something like this:
GM: okay, we're ready to start a new campaign that's not D&D this time. What characters do you want to play?
Player 1: I want to play a Fighter. A prince this time.
Player 2: I want to play a Cyclops. Can I play a Cyclops? A noble woodsman, last of his kind.
Player 3: How bout this time I play a wizard that keeps his spellbook on note cards.
GM: this is going to be a sci-fi campaign, okay?
Player 1: ... a space prince then?
Player 2: looks unblinkingly at GM
Player 3: fumbled through the spell cards he'd already made.
GM: sighs