This is the first episode in which the Flying Sub makes an appearance in the opening credits.
The title refers to a biblical term for sea monster and is also known as the gate keeper or one of the seven princes of Hell.
This episode takes place in the 1970s.
In "Lost in Space" (1965) {The Oasis (#1.9)}, Dr. Smith grows to giant size, and Prof. Robinson says he'll try to reverse it-- just as Nelson said to Sterling here-- 4 DAYS EARLIER (11-10-65 / 11-14-65).
This episode features not one, but two actors that would later appear in Star Trek: Karen Steele and Liam Sullivan.