Marshtomp

You have to look for it along the shoreline, in the mud left behind by the receding tide. The Pokédex entries all insist on the same thing: it lives buried in mud, and spending so much time there has given it legs sturdy enough to keep its balance on ground where nothing else can stand. It sleeps buried beneath the sand. When the tide is out, it plays in the mud.

A very thin, sticky film covers its entire body, allowing it to stay on land without drying out. Its hindquarters have developed enough for it to walk only on its back legs: 70 centimeters and 28 kilos on a biped that, according to its own entry, moves faster through mud than through water. That's the odd detail, and it comes from a Pokémon whose official category is the Mud Fish Pokémon.

It occupies the middle step in the Mudkip line: it joins at level 16 and leaves at 36 on the way to Swampert. Twenty levels in transit, which in a Hoenn playthrough is enough to cover the longer half of the journey without ever becoming the final form.

The 405 points are distributed with an obvious bias: 85 Attack against 60 Special Attack, and three identical 70s in HP, Defense, and Special Defense. Speed stays at 50, so it almost always moves second. The spread calls for physical attacks, and that's where the mismatch appears: what it learns by leveling up leans special — Muddy Water at 40, Hydro Pump at 55, Mud Shot from the start — while its best physical attacks, Earthquake, Waterfall, and Aqua Tail, only come through TMs.

Torrent powers up Water-type attacks in a pinch, when it has little HP left. Damp, its Hidden Ability, merely stops the opponent from self-destructing, which in practice covers two moves and nothing else.

The Water and Ground typing is its best asset. Ground's immunity removes Water's Electric weakness, it resists Fire, Rock, Poison, and Steel, and only leaves one weakness exposed. The problem is that this one weakness is quadruple: any ordinary Grass-type attack knocks it out from the other side of the field, and its 70 HP gives it no room to negotiate.

Without evolving, it has no place in serious competition, because Swampert puts the same typing on 535 points instead of 405. Where it does work is in a normal Hoenn playthrough. Mauville's Electric-type Gym is the obvious example: Ground's immunity makes the leader's team's main attack completely useless. The same goes for the region's Fire- and Rock-types, and Amnesia at level 35 suddenly patches up the special side of its defenses if it needs to take a hit.

It belongs to the Monster and Water 1 Egg Groups, the dual membership it shares with much of the amphibian lines. The gender ratio is seven males for every female: 12.5% female, the usual figure for starters, so starting a breeding line of your own means finding the female or resorting to a Ditto.

Twenty incubation cycles amount to about 5355 steps. The egg can produce moves it can't learn any other way, and some of them are genuinely useful: Yawn to force switches, Counter and Mirror Coat to bounce hits back from such low Speed, Ancient Power, Bite, Curse, and Wide Guard for double battles.

Evolution has no unusual conditions. Mudkip becomes Marshtomp at level 16, and Marshtomp becomes Swampert at 36, with no items, times of day, or friendship involved. The growth rate is Medium Slow, meaning slow early on and making up for it later.

Its registered habitat is the shoreline, and its catch rate, 45, puts it among the difficult Pokémon to catch with a regular Poké Ball: the same figure carried by starters, which under normal circumstances you don't throw balls at. Defeating it gives 2 Attack EVs and 142 base experience.