The names "Jeffrey Clive" and "Dell Frye" are tributes to actors Colin Clive and Dwight Frye, who played Dr. Frankenstein and his assistant Fritz in Universal's Frankenstein (1931).
Owing to the time and money spent on the Hulk out scene with Dick Durock portraying Del Frye's creature, only one appearance for Lou Ferrigno's Hulk was possible for the episode.
In addition to the names of "Jeffrey Clive" and "Dell Frye", the town that David visits, Vissaria, is also a tribute to Universal horror movies. This is the name of the fictional European village where Frankenstein meets The Wolfman, House of Frankenstein, House of Dracula, and other Universal monster movies are supposed to have taken place.
This two-parter is the only time in the series that the Hulk encounters another super-powered character (not counting Thor and Daredevil who appeared in the TV Movies that followed the show).
Walt, the kid who dies at beginning, is actor Jack Magee. His real name matches Jack Colvin's "Jack Magee". Colvin's Magee appears in Part 2.