This Marshtomp is a water/ground-type Pokémon that Brock caught as a Mudkip. It is the second Pokémon Brock acquired during his Hoenn journey.
After evolving, Brock's Marshtomp became a strong Pokémon often used to settle feuds or just in simple battle. Marshtomp is a well mannered Pokémon which takes after its trainer a little bit in regards to romance. Brock notably used Marshtomp in a Pokémon Contest against May. Brock's Marshtomp debuted in "A Chip Off the Old Brock".