Cleopatra, the meat eating plant from The Addams Family (1964) makes a cameo appearance. This creature is also seen in Charlie X (1966). Fred Freiberger, who produced on this show, also produced on Star Trek.
When West slides down the slide after passing the mouse trap, the clip of him sliding down is the same clip from The Night of the Golden Cobra (1966). Except the original had West sliding from the upper-right to lower-left of the screen - so the scene was flipped for this episode.
First full color episode with Michael Dunn as "Dr. Miguelito Loveless".
The spider shown is a Red Kneed Tarantula, common in western Mexico and popular in the US as a pet. As tarantulas do not spin webs or descend on threads someone had to dangle the spider in front of the camera.
Dr. Loveless' henchman Voltaire (Richard Kiel) does not appear in this episode.