The "Goblin" in this episode is the same costume used as the "Troll" in Samantha and the Troll (1971) (and same actor).
This episode was originally meant to include a client that Larry and Darrin have to deal with who hates Halloween however the idea was written out when the script came 10 pages over the limit.
When Samantha takes the kids out trick-or-treating, the first house they stop at (where a woman answers the door) is the same house that was used as the Baxter residence in the sitcom Hazel (1961), as well as the home of TVs Gidget (1965). It's located right next to (to the left of) theBewitched (1964) home, on Blondie Street at Warner Ranch.