In "Pikachu's Summer Vacation," Ash's electronic Pokédex, Dexter, acts as the primary narrator. It delivers factual commentary on Pokémon behaviors and biological traits witnessed at the Pokémon-themed resort. Dexter identifies Togepi as the Egg Pokémon, noting its low hunger tolerance when it cries upon arrival. It later labels Bulbasaur's improvised melody, used to soothe Togepi, as the "Bulbaby." When Snubbull appears with Raichu, Cubone, and Marill, Dexter identifies Snubbull as a newly discovered Pokémon species.
During conflicts between Pokémon groups, Dexter offers generalized observations about typical Pokémon behavior, stating they are usually peaceful creatures who cooperate and avoid battles unless instructed by trainers. It also demonstrates multilingual capabilities by translating Pokémon languages into human-understandable dialogue.
Dexter narrates key incidents: the swimming race between Squirtle and Marill, the electrical confrontation between Pikachu and Raichu, Charizard becoming trapped in a pipe, and the collaborative rescue effort involving both groups of Pokémon. Its narration concludes as the Pokémon reconcile and depart the resort at sunset.