When Slappy is seen in the basement, his head is completely different. This is because this is the mask used by the actress that was Slappy in "Night of the Living Dummy III". It was used on a dummy double when Jillian bangs Slappy's head on the work table after he bites her, to keep the dummy's head from cracking.
This is the second time that Ron Stefaniuk provides both the puppetry and voice for Slappy. He had previously done the puppetry in "Night of the Living Dummy III" two-part story, but Cathal J. Dodd provided Slappy's voice in "Night of the Living Dummy III" when Stefaniuk was unavailable due to schedule conflicts. This is Slappy's last regular appearance on the show. However, Cathal J. Dodd provided the voice of Slappy for the "Viewer beware, you're in for a scare" quote in the opening credits of the final season.
When Katie and Harrison are watching a scary movie, the footage is actually from three previous episodes: "The Scarecrow Walks at Midnight", "The Werewolf of Fever Swamp", and "Welcome to Camp Nightmare".
Three of the dummy heads used from "Night of the Living Dummy III" appear in this story. The broken, severed heads of Slappy's "rivals" in Jimmy O'James' home are the heads of the Rocky and Zane dummies. The damaged, severed dummy head near the end is the head from when Mr. O'Dell tries to glue Slappy's right eye back on his cracked face.
When Jillian goes to return Slappy to Jimmy, she is first seen standing behind a gate. As the gate lifts up, you can see that someone had written in black paint 'Don't worry, be happy,' but someone had taken red paint and had written 'SL' over the 'H' so the message now read 'Don't worry, be Slappy'.
One of four episodes to be based on a Goosebumps sequel book without its predecessor having been adapted for TV (two of the others were previous Night of the Living Dummy stories; the third was "Return of the Mummy").