Meowth

History
Meowth is the brains of the Jessie/James/Meowth trio in the pokemon anime. When he was younger, Meowth lived on the streets in Hollywood after he came there in search of fame and fortune. He was a member of a gang of street Meowth that was led by a Persian; this gang annoyed the humans in town, stealing food and causing trouble in general. One day, Meowth came across a female Meowth named Meowzie. Since she rejected him and preferred the company of her rich human mistress, Meowth attempted to make himself stand out from other Meowth and become more human-like to make himself "worthy" of her. Thus, he painstakingly taught himself to speak human language and walk upright like a human. When he approached her after this transformation, she once again rejected him, calling him a freak. Heartbroken, Meowth remembered the first human word he learned to speak - "rocket" - and was inspired to join Team Rocket.

In Go West, Young Meowth, Meowth, Jessie, and James returned to Hollywood while following Ash, and Meowth was reunited with Meowzie, who had since been abandoned by her mistress and was forced to join the gang of street Meowth. Meowth fought his former Persian leader to win Meowzie's love, and won, but Meowzie demonstrated that her loyalty was with Persian since he took care of her when she needed it, and Meowth was once again heartbroken.

Because of the effort Meowth exerted while learning to speak and walk like a human, he has not learned the signature move of his species, Pay Day. In Meowth Rules, Meowth was worshiped by an island of people who believed that he could bring them riches with Pay Day. When he was caught in a battle meant to induce Pay Day, Jessie and James had to secretly bail him out by throwing the last of their spare change and some of James's prized bottlecaps in order to appease the islanders. Upon learning of its species's love for gathering coins and shiny objects from Ash's Pokédex later in Do I Hear a Ralts?, Jessie criticized him for not doing so.