Grookey is a Grass-type Pokémon introduced in Generation VIII.
It evolves into Thwackey starting at level 16, which evolves into Rillaboom starting at level 35.
Along with Scorbunny and Sobble, Grookey is one of three starter Pokémon of Galar available at the beginning of Pokémon Sword and Shield, and were the first Generation VIII Pokémons to be revealed to the public on February 27, 2019.
Grookey beats this stick rhythmically against the surfaces of all sorts of objects. This has been observed to cause grass to grow, and wilted flowers and leaves seem to regain their color when Grookey drums nearby. The stick used to be a branch from a forest where troops of Grookey lived, and it has a special power due to being exposed to the energy within Grookey's body.
Grookey's green fur can create energy from the sunlight, similar to how plants use their green leaves to photosynthesize. It is said to be full of boundless curiosity.