Ash's Larvitar (Japanese: サトシのヨーギラスSatoshi's Yogiras) was a Pokémon that Ash cared for briefly in the Johtoregion. Like Haunter, Ash did not catch this Pokémon, and therefore, he did not officially own it.
In the next episode, the Egg hatched into Larvitar. Ash and his friends were forced to take it to a Pokémon Center when its skin temperature quickly fell. Overnight, Ash entered Larvitar's memories, which revealed that a motorcyclist fell onto the ground and Larvitar's Egg broke free of its crate in the process. Larvitar's Egg traveled downstream, where it was kicked around by a crowd of people and then narrowly avoided being hit by an oncoming truck.
In Address Unown!, an Unown teleported Ash, Brock, and Misty to a dimension that physically manifested images and experiences from Larvitar's life. Ash and his friends then reached a giant Larvitar Egg with holes in it, as well as a large crystalline thorn sticking out of it. Inside the holes were images of Ash, Misty, and Brock. Both Misty and Brock appeared in black and white, symbolizing Larvitar's distrust towards them. After Ash touched the thorn, he, Misty, Brock, Pikachu, and Togepi were transported inside the Egg and into another dimension where Larvitar was seen sleeping. There, Ash and his friends received visions of Larvitar as an Egg. The group then heard Larvitar's voice as it was kidnapped by the Pokémon Poacher Brothers and sensed its mother being brutally attacked. It was later separated from the poachers and mistakenly kicked around. Larvitar's past manifested into thorny branches encasing it, developing into a block of crystal. Together, Ash, Misty, and Brock were able to destroy the branches around Larvitar and help it open up more.
Larvitar and Ash
Since that incident, Larvitar became more comfortable around Misty and Brock, but it still hardened around other human beings. It was then reunited with its mother in Mother of All Battles!, who at first believed Ash and his friends were harming her child. Tyranitar eventually calmed down once she realized Ash and his friends' peaceful and benevolent actions around Larvitar. However, the poachers that initially stolen Larvitar, the Pokémon Poacher Brothers, returned to capture her, but they were eventually captured through the teamwork of Ash, his friends, Ranger Mason, and Larvitar. Afterwards, Larvitar was left at Mt. Silver.
Larvitar reappeared in a flashback in Alola, Kanto! while Ash, Brock, and Misty were reminiscing about their travels together.
Personality and characteristics
Larvitar was particularly shy around humans after birth, and it would subsequently often Harden itself towards them. The trauma that Larvitar suffered as an Egg was the main reason for its introverted nature.
During its adventures with Ash, Larvitar gradually learned to appreciate life and everything around it. Larvitar became very close to Ash and his Pikachu, and went on to make some friends with other Pokémon as well.