In this episode, Metapod and Kakuna's evolution processes are depicted as their shells cracking and their evolved forms emerging, leaving behind an empty carapace, similar to real-life insects' emergence from pupation. In later episodes, however, Metapod and Kakuna are shown to evolve like any other Pokémon.
Ash's Metapod evolves into Butterfree and learns the move Sleep Powder.
During the Metapod vs. Metapod battle, each side uses Harden in a futile attempt to defeat the other. However, Ash's Metapod should technically know Tackle as well, since it evolved from a Caterpie. It does, in fact, appear to use this move later to protect Ash from a Beedrill's Twineedle attack.
This episode features the first character of the day in the anime, namely Samurai.
Ash's Pidgeotto is revealed to know Sand Attack while his Metapod is revealed to have learned Harden.