In the scene where Flanders is at Burns's Mansion trying to pitch recycling Burns states, before releasing the hounds, "I see you have your running shoes on. That's a good thing." You can see here that Flanders is wearing his Assassin shoes from Bart's Dog Gets an F.
When Santa's Little Helper is remembering all the good times he's had with Bart, he recalls when Bart mistakenly hit him in the eye with a Frisbee in Bart's Dog Gets an F.
When the family is posting up lost signs for Santa's Little Helper, they are shown putting one on a pole over the one of Principal Skinner's "Have you seen my body today?" signs from "Bart the Murderer".
Santa's Little Helper is seen going down Michael Jackson Expressway, a name which was given to this road in "Stark Raving Dad".
Following the controversy behind the Leaving Neverland documentary and "Stark Raving Dad" getting banned because of it, reruns shown on the American channel FXX and Australia's Nine Network digitally blur out "Michael Jackson" on the map showing Santa's Little Helper's adventures. Disney+, the DVD versions (both older and newer pressings), and the 4:3 airings have this uncut.
Among the books seen burning in Homer's fireplace is Fatherhood by Bill Cosby, a book given to Homer in "Saturdays of Thunder".
Julie Kavner voiced a teacher in the teacher's lounge, using her natural voice.
Smithers claims that Crippler has been at the Springfield Nuclear Power Plant since the late 1960s. This would make him at least in his early 30s at the time of the episode, which is older than any dog has been known to live in real life.
References[]
The scene where Santa's Little Helper is brainwashed (by having his eyes pinned open and watching footage) is a parody of the rehabilitation process of Alex DeLarge in Stanley Kubrick's A Clockwork Orange.
When leaving the vet for the first time after finding out Santa's Little Helper is sick and the family is in the car. It shows they are in Marge's station wagon since Bart and the dog are in the cargo area and the car is red. But when the camera changes to show the car going down the highway the car looks like Homer's sedan and it is also pink like his car.
Lisa's neck/chest
When Burns complains about dogs to Smithers, the background flickers for a few frames.
When the Simpson family is first calling for Santa's Little Helper to come back, Lisa's neck and the top of her chest briefly turn pink like her robe.
Santa's Little Helper's yellow leg
When Marge is looking through pictures of Santa's Little Helper, in the picture of him biting Homer, the end of Santa's Little Helper's front leg is briefly colored yellow.
In this episode Santa's Little Helper saves a baby from a burning house, fights a bear and defends Bart from hounds. However, in "Old Yeller-Belly", he is depicted as a coward. He could have gradually become more cowardly over the years.
Mr. Burns said that "Dogs are idiots" despite owning numerous attack dogs himself. Mr. Burns only cares about money and no one else, not even his assistant Smithers who pines for him, and it's pretty much shown in this episode -- and others -- that he has dogs as a way to scare off people and trains them to be vicious, soulless killers.
