Topanga's sister Nebula appears in this episode but is never seen or referred to again. Hereafter, Topanga is an only child.
When challenged by Eric, who says he is sounding a little jealous that Topanga is showing feelings for Eric and not him, 11-year-old Cory sarcastically replies that he wants to be Topanga's boyfriend and name their children Chewbacca and Plankton. Cory and Topanga eventually did have children, named Riley and Auggie, in Girl Meets World (2014).
The poem that Mr. Feeny is reading to the class when Eric returns is "The Cremation of Sam McGee" by Robert W. Service and was published in 1907.
In She Loves Me, She Loves Me Not (1994) in which Topanga has a crush on Eric, she introduces her sister Nebula. After that episode, Nebula is never heard from or mentioned again by any of the characters, including Topanga.