Marill

A semiaquatic rodent with a float tied to its tail. The design mixes a water rat with a beach ball or a lifebuoy, and the Pokédex explains the mechanism without metaphors: the round tip of its tail stores oil that is lighter than water, and that alone is enough to keep an 8.5-kilogram creature afloat. The official category, Water Mouse Pokémon, doesn't hide much either.

The entries insist on two traits. Its fur repels water, so it can spend hours playing in a river without getting wet and dries instantly after leaving an icy sea. Its tail is flexible and elastic too: it wraps it around a tree to fish without being dragged away by the current. When that ball pokes above the surface and moves around, the animal is underneath, half-submerged and looking for aquatic plants. The oil doesn't just help it float; it is also a pantry — the tail stores nutrients in that form.

At 0.4 metres tall, it's one of the Pokémon that can fit in a backpack, and its role in the line is the middle stage between Azurill, which still can't swim properly, and Azumarill, which already lives in the water full-time. Of the three forms, it's the only one that is seen both in and out of the river.

The numbers make its game plan obvious straight away: 250 points in total, with 70 HP and the rest split between two 50-point defences, 40 Speed, and 20 in both attacking stats. That physical 20 is the joke everything is built around, because Huge Power doubles it and turns it into an effective value of 40. That's still not much. Thick Fat, the other common ability, softens Fire- and Ice-type moves, which wouldn't deal extra damage to it anyway. Its Hidden Ability, Sap Sipper, is the most useful of the three: it makes Grass-type moves harmless — one of the four weaknesses of the Water and Fairy combination, alongside Electric, Poison and Steel — and boosts its Attack on top of that.

Defensively, the typing is one of the good ones: it resists Fire, Water, Ice, Bug, Dark and Fighting, and is immune to Dragon. The problem is that 50 and 50 don't take much punishment, and its best offence arrives late. Aqua Tail doesn't appear until level 19 and Play Rough until 21, when level 18 has already turned the creature into something else if the trainer hasn't hit the B button in time.

It's not a serious battle Pokémon: everything it offers is done better by its evolution, with better numbers. Where it does work is in a normal playthrough, as early Water-type coverage with Bubble Beam at level 6 and Charm at 9 to cut whatever is in front of it down to half Attack. In double battles, Helping Hand is available from level 1.

It belongs to the Water 1 and Fairy Egg Groups, a pairing that opens up breeding with both river wildlife and half the Fairy-type section. The gender split is perfectly even: 50% female, so building your own line doesn't depend on luck. Its 10 incubation cycles are equivalent to about 2805 steps, putting it among the shorter stretches in the Pokédex.

The Egg Move list is empty in the reference game: whatever it learns, it learns by levelling up or with TMs. It is worth knowing, though, that breeding two members of this line with a parent holding Sea Incense changes the Egg — instead of another Marill, an Azurill hatches, which is the only way to obtain the baby form.

The evolution has two directions, and only one of them is automatic. It comes from Azurill when it levels up with friendship at 160 or higher, starting from a base friendship of 70, which means taking it for a walk for a while. It evolves into Azumarill on reaching level 18, with no items or conditions. With a Fast growth rate, that level 18 arrives sooner than expected.

In the wild it lives along riverbanks, and its catch rate, 190, puts it among the easy ones: a regular Poké Ball with the opponent a little worn down is usually enough.