Chespin seems to resemble a porcupine or hedgehog. It has a tough spiky green chestnut-like shell covering its head and back. Chespin has brown fur, a large pink triangle-shaped nose, black oval-shaped eyes, and a toothy grin. It has sharp claws on its large feet, and a pink tip on the end of its pointed green tail.
Despite having a curious nature that tends to get it in trouble, Chespin keeps an optimistic outlook and doesn't worry about small details.
Chespin can be evolved into Quilladin starting at level 16, and into Chesnaught starting at level 36.
Chespin is the first Grass-type starter Pokémon that is not reptile-based but based on a mammal, in this case a rodent or a marsupial. Judging by its Japanese, English, French, German, Spanish, Italian and Korean name, it appears to be based on a porcupine.