Jessie trades her Pumpkaboo with Count Pumpka's Mawile, resulting in Pumpkaboo evolving into Gourgeist. However, Jessie later trades Mawile back to Count Pumpka for her newly evolved Gourgeist.
This episode marks the second time a main character trades a Pokémon for another one, but later trades it back. The first time was in Battle on the St. Annu! (1997), 866 episodes earlier.
Jessie not knowing that her Pumpkaboo (and then Gourgeist) is a female is a callback to The Worst Togepy Ever! (2009), where Jessie did not know her Yanmega was a female either.
This episode confirms that Jessie's Pumpkaboo (and later, Gourgeist) is female and Super Size.
The cosplays seen in this episode include: Ash as a Snorlax; Pikachu as a Psyduck; Serena as a Red Flower Florges; Clemont as a Watchog; Bonnie as a Ludicolo; Dedenne as a Corphish; Chespin as a Pikachu; Jessie as a Mismagius; James as a Gourgeist; Meowth as a Banette; Wobbuffet as a Sawk; Inkay as a Pikachu. This is the second time Inkay is disguised in a Pikachu costume, with the first time being in Ta-da! Fake Satoshi Appears!! (2014), while Meowth's Banette costume is the same one he wore in It's Ghost Time After School (2008) and Onvern Appears! Legend of the Comet and the Hero!! (2013).