Pikachu's Vacation (Japanese: ピカチュウのなつやすみ, Pikachū no Natsuyasumi?) is a 21-minute short movie that is shown before Mewtwo Strikes Back in both the theatrical and the DVD version of the main movie. It is the first of the “Pikachu shorts” in what would be a traditional process of hosting a 20+ minute mini-movie before the main Pokémon feature that would last up until the 6th movie. Pikachu's Vacation, like the five Pikachu shorts that would follow, focuses primarily on an action-packed affair involving solely the Pokémon seen from the anime as they take part in a scenario that eventually illustrates a moral.
In Pokémon fan communities, Pikachu's Vacation was noted for introducing the never-before-seen Pokémon character Snubbull (albeit spelled Snubble), as well as the first primary anime appearance of the already popular Marill. This became a tradition for all Pikachu shorts, as they were used to introduce new Pokémon from the upcoming “generations” of Pokémon games, cards, and anime material.
When Ash and his friends stumble upon a Pokémon-only vacation resort, they decide to let their Pokémon have a day of fun and relaxation and let all their Pokémon out as the trainers go relax on their own. Pikachu and the Pokémon (Bulbasaur, Charizard, Squirtle, Pidgeotto, Geodude, Onix, Vulpix, Zubat, Staryu, Goldeen, Psyduck, and Togepi) go off into the resort and immediately contend with an unhappy Togepi, which they succeed in doing. Soon, a group of border-ruffian Pokémon comprised of a Raichu, Cubone, Snubbull, and Marill come along and immediately cause trouble for Pikachu's group. The ensuing standoff soon becomes a series of competitions such as a swimming race. Their increasingly passionate rivalry soon comes to a standstill when Pikachu's companion Charizard finds its head stuck in a tight storage receptacle. Putting aside their squabble, Pikachu and Raichu's groups join together to release Charizard, and they soon find themselves as friends for the rest of the day. At the end of the day, Pikachu and his fellow Pokémon leave the resort with fond memories and new friends and rejoin their trainers.
This was the first time Charizard was seen crying.