Swampert

Swampert is the final form of the Water Type starter Pokemon Mudkip for the Hoenn region. Swampert, in this very case, is a Pokemon. Swampert is a dual Water and Ground type Pokemon.

As a Mudkip
Mudkip is first seen when he comes into the Home, soaking wet from the rain. He comes over and playfully splashes water onto Snivy. He then comes straight over to Piplup and, without hesitation, asks her out for a date at the Romantic Restaurant, and this surprises Oshawott.

Mudkip pulls Oshawott away from Snivy for a moment when he sees him struggling to ask her out. Mudkip tells Oshawott to have pride when asking her out. Mudkip is proud of Oshawott thereafter.

At the restaurant, Mudkip is commonly seen telling the other males, "That's why she's mine, boys," referring to Piplup. When Mudkip and Piplup take a different path from Snivy and Oshawott, he turns around when no one is looking and gives Piplup a kiss.

When they get Home, Mudkip is often protective of Piplup. He then puts Tepig's life to an end when Tepig had hurt Piplup really bad. He took Piplup to the Pokemon Center while Snivy took Oshawott.

At Totodile's and Emolga's wedding, he is the one who walks Emolga down the aisle. Later, Mudkip and Piplup have their own wedding, and this later results into the two having an egg, which hatches into a Manaphy that is extraordinary, as Manaphy had a female gender.

As a Marshtomp
Mudkip evolved into Marshtomp during a robbery, along with Piplup, Snivy, Oshawott, and Totodile.

He, along with the other parents, are very worried upon coming Home to find their daughters giving birth. Marshtomp and the others are seen muttering that they were too young to be grandparents at their age.

At the battle with Zoroark and his evil gang, he, Prinplup, Servine, Dewott, Croconaw, and Emolga are seen standing over a Lillipup and Pidove, protecting them from a Druddigon that was going to crush them.

Later, after the reporter man finishes saying that the world would end due to a malfunctioning crystal, Servine suggests that she, Dewott, Marshtomp, Prinplup, Croconaw, and Emolga go on a journey to save the crystal and the world. They all agree.

As a Swampert
Marshtomp evolved into Swampert along with Prinplup, Servine, Dewott, and Croconaw due to the fact that they were all being attacked by enraged Beartic at the Icy Mountain.