The episode: “Merlin’s Shop of Mystical Wonders,” ep. 1003
The riff: A bit of a mysterious riff here. Tom says it right after the heroine asks about a curious, elongated purple and white stone in Merlin’s shop. Merlin’s wife calls it “very special” and then says it is something that is tough to make out, but sounds like “a laurel.” Tom then adds something that sounds like “a bassarino.”
The explanation: I am guessing that what he was actually saying was “Bass-Oreno,” a reference to a long-running fishing lure for catching, you guessed it, bass. The three-hooked jig was manufactured for almost a century. I suspect this is the reference because the MST3k crew has made plenty of fishing references before, likely due to the fact that they all seemed to grow up in the rural Midwest. The stone also is similar-looking to a Bass-Oreno lure.
Novelty factor: Definitely never heard of this lure. I doubt I could name any brand-name fishing lure, so that’s probably a bit of a gap in my knowledge.