According to Sid Haig, when Lon Chaney Jr. finished the scene where Bruno talks about the toy, the crew was in tears. Chaney also received a standing ovation and wasn't able to leave the set for five minutes.
The rocking chair that Virginia ties Peter to as she plays her spider game was an antique that belonged to director Jack Hill's grandmother. It was destroyed during filming.
Sid Haig admitted to avoiding Lon Chaney Jr. for the first two days of filming, simply because he wasn't sure what to say to the veteran actor. One day Chaney was needed for and Haig was sent to Chaney's trailer to retrieve him. Haig nervously knocked on the door and said, "Excuse me, Mr. Chaney. You're needed on set." Chaney told Haig, without skipping a beat, "Stop that. I'm not Mr. Chaney. I'm Lon. You're Sid. Let's leave it at that." Haig later said that this interaction put him completely at ease.
Thought to be a "lost" film in the 1990s, it was learned there was a badly-dubbed 16mm VHS copy in release. Writer/director Jack Hill found the original negative, got a clean digital transfer from it and put that in circulation. As the picture was not copyrighted, he was able to market it on his own. Hill added a scene cut from the original theatrical release and promoted it as the "Director's Cut".