I am the infamous predecessor of................

Known as 'tiny mouse',this not so known species of Pokemon(X) is the predecessor of another famous species of Pokemon.X made his first appearance in the Pokemon gold and silver and later came out in forms of merchandise and other items of the franchise.X is small ground dwelling rodent which is yellow in colour.
My question is simple.Id X.

Ans-Pichu the predecessor of PikachuCorrect ans is only Pichu)
Cracked by Muhamad,Nandu,Suman,