Marshtomp evolves from Mudkip at level 16 and into Swampert at level 36. A sticky coating on its skin lets it survive out of water, but it weakens if that skin dries, so it keeps to mudflats and even sleeps buried in mud. Marshtomp is the only middle evolved form of a Water-type first partner Pokémon with two types, and it and Swampert are the only first partner Pokémon with a 4x weakness to another first partner Pokémon type, Grass. Its design seems to draw on the mudpuppy or mudskipper, and the single fin on its head resembles the crested helmet of a Roman murmillo gladiator.
In A Chip Off the Old Brock, Brock's Mudkip evolved into a Marshtomp and remained on his team until it was left in Pewter City. In ZigZag Zangoose!, Nicholai's Mudkip was revealed to have evolved into a Marshtomp, which he used in a battle against Ash where it was defeated by Treecko's Pound. In Up to Your Neck!, Ash and Goh freed a Marshtomp trapped in dry mud with help from a Ludicolo.
Marshtomp's first cards appeared in the 2003 Ruby & Sapphire base set, illustrated separately by Mitsuhiro Arita and Ken Sugimori. It also has a Nintendo Black Star Promo by Mitsuhiro Arita. Dragon and Emerald each added Uncommon prints by Atsuko Nishida, and Crystal Guardians contributed two more. The Diamond & Pearl era added Great Encounters and Supreme Victors printings, and later single cards followed in Primal Clash, Celestial Storm, and Fusion Strike.
Marshtomp's first card, a 2003 Ruby & Sapphire Uncommon illustrated by Mitsuhiro Arita.
Dragon's Uncommon Marshtomp illustrated by Atsuko Nishida.
Crystal Guardians's Rare Marshtomp illustrated by Kagemaru Himeno.
Fusion Strike's Uncommon Marshtomp, illustrated by tetsuya koizumi.
Marshtomp evolves from Mudkip at level 16 and evolves into Swampert at level 36.
Brock's Mudkip evolved into a Marshtomp in A Chip Off the Old Brock, and Nicholai used a Marshtomp against Ash in ZigZag Zangoose!.
Our catalog lists 13 Marshtomp cards across 11 sets, from the 2003 Ruby & Sapphire base set through Fusion Strike.

ヌマクロー
Water · Ground
No published index yet — too few of Marshtomp’s cards trade often enough to strike one.