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".
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").