Though it looks like Diglett, Wiglett is an entirely different species. The resemblance seems to be a coincidental result of environmental adaptation.
Hidden Ability
Contact with the Pokémon lowers the attacker's Speed stat.
The Pokémon gets scared when hit by a Dark-, Ghost-, or Bug-type attack or if intimidated, which boosts its Speed stat.
Boosts the Pokémon's evasiveness in a sandstorm.
