Clemont's Chespin is a grass-type Pokémon owned by Clemont.
Chespin was one of the three Starter Pokémon that Professor Sycamore had kept to give to new trainers.
By nature, Chespin is extremely gluttonous especially when it comes to Macaron, which is its favourite to the extent that it would put itself in danger just to get them. It also tries to help people who are in danger, like when it tried to chase after Team Rocket in order to save Professor Sycamore, Serena, & Bonnie. It is also intelligent as he was able to understand the oddness of the pieces of Macaron that where left behind by Serena as markers, or was able to deduce that the cord it came across before was actually the power source for the "Mega Mega Mega Mecha Meowth" and thus tried to unplug it.
After it was saved by Clemont, it created a special bond between them which lead it to decided that it wanted to travel with him.