This Tauros is a Pokémon who belongs to a wandering trainer who was challenged by Ash as he wandered around Mandarin Island.
During its battle with Ash Ketchum, Squirtle managed to defeat Persian with a Skull bash after enduring its Thunderbolt. The trainer then used Tauros who quickly defeated Squirtle but lost to Charizard's Flamerthrower even though it used Take Down on it first.