The episode: “The Magic Sword,” ep. 411
The riff: Intoned in a Russian accent by Joel as a swirling orange vortex takes up the whole screen.
The explanation: This is a reference to characters from the short-lived 1960 cartoon “Tooter Turtle,” which was apparently part of a show called “King Leonardo and his Short Subjects.” In each episode the slow-witted turtle would ask his friend Mr. Wizard the Lizard for his help in traveling to a new time period or locale, before bungling it all up and asking the wizard to take him home. Mr. Wizard would then speak the magic words, bringing Tooter safely back.
Novelty factor: Had no clue. I don’t think this is the only time that this particular riff is used, either, because it sounds very familiar. It’s clear that childhood cartoons had a big impact on the writers of MST3k, in the same vein as the previous “Scott McCloud, Space Angel!” riff.