Homer thinks the title creatures from Gremlins will be at the animal retirement home. He then says "I'm going to get them so wet", referencing that in the movies when they get wet they multiply.
Antonio Fargas makes an appearance as Huggy Bear (from Starsky & Hutch), who has mistakenly been caged in the animal retirement home. This is not Huggy Bear's first appearance on The Simpsons, but it's his first speaking role. In "Homie the Clown", we saw "The Son of the Guy who played Huggy Bear".
In the same scene, which takes place in an old mill, his rubber duck barely escapes being crushed by the rotating gears. This scene is a tribute to Walt Disney's 1937 classic The Old Mill.
The episode reveals that Mr. Teeny's real (monkey) name is Louis.
Rod makes a paper plate mask of Todd and vice versa. This may be a reference to a Simpsons Halloween Comic, in which Rod dresses up as Todd and vice versa.
Maude Flanders is shown looking down on her sons from heaven, saying "My little boy is growing up". Maggie Roswell voiced her, but was credited in the premiere airing. When it reaired, the credits were amended to include her name.
When Marge speaks to Ned, she consults a Flanders-English dictionary, and Ned uses an English-Simpson dictionary.
This is the second episode where a Simpson is criticised for being a bad babysitter, while something happens to Bart (first one was "My Sister, My Sitter").
This episode confirms many in the Internet community who say that Ned is very overprotective of his sons without the help of a female companion. He marries Edna and things were fine but with her death, Ned has gone back to overprotecting his kids.
If Flanders does not like using computers, it would not be possible that he comes up with his internet-based company FlanCrest Enterprises on episode "Das Bus".