Grimer

It slips down sewer pipes to drink dirty water. Grimer’s sludge body is elastic enough to pass through any opening, no matter how small, and come back together on the other side as a puddle again.

The Pokédex entries never quite agree on where it came from. Some say the sludge transformed when X-rays reflected by the Moon filtered into the water; another has it emerging from the mud in a polluted area on the seafloor. They agree on everything else: it appears in disgusting places, grows by absorbing the toxic waste discharged by factories, and constantly gives off a bacteria-laden, contaminated fluid from its entire body. Those bacteria aren’t just for show. If their numbers drop, Grimer’s own life is at risk.

One entry sounds like bad news and means the exact opposite: the population has declined considerably, and the reason is that there is less industrial waste left to eat.

Its official category is the Sludge Pokémon, and at 0.9 metres and 30 kilograms it is a pile of mud with two arms, two eyes and an open mouth. It evolves into Muk, and that is where the line ends, making it one of the shortest in Kanto. There is also an Alolan Form with its own colour and diet.

Its 325 base points are badly distributed even for what you expect from a first-stage Pokémon. The 80 HP and 80 Attack hold the set together; 50 Defense, 50 Special Defense and 40 Special Attack are filler numbers, while its 25 Speed leaves it among the slowest in the generation. It moves last against almost anything, and with those defenses that means taking two hits for every one it gives back.

Of its three Abilities, the only one that does anything measurable is Sticky Hold, which stops opponents from stealing its held item and therefore shuts down Thief, Trick and Switcheroo. Stench can make the opponent flinch because of the bad smell. Poison Touch, its Hidden Ability, poisons on contact, and it fits Gunk Shot — 120 physical power, learned at level 40 — because it is a contact move.

Attacking only from the Poison type is the other drawback. That type hits Grass and Fairy for super effective damage and nothing else; Poison, Ground, Rock and Ghost resist it, while Steel is immune, so any opponent of those types shuts down the entire offense. TMs partly cover the gap: Dig and Mud-Slap for Steel and Rock, Fire Punch and Thunder Punch for whatever is left.

Where it does the job is in a normal playthrough, thanks to two moves that arrive early: Toxic at level 26 and Sludge Bomb at 29. With 80 HP, it lasts long enough to poison whatever is in front of it and retreat. It is no wall: Acid Armor does not appear until level 43, when it is already time to evolve it.

It belongs to a single Egg Group, Amorphous, the box for creatures with no fixed shape. The gender split is 50%, so there is no need to hunt down a female or use a Ditto to start a breeding line. Its 20 Egg cycles work out at around 5355 steps, neither short nor long.

Of its nine Egg Moves, two are worth the trip: Shadow Punch and Shadow Sneak, physical Ghost-type attacks that it cannot learn any other way — what it gets by TM in that type, Shadow Ball and Hex, is special, and it has 40 Special Attack. The third interesting one is Curse: on a Pokémon that is not Ghost-type, it raises Attack and Defense in exchange for Speed, and losing Speed when you already have 25 costs practically nothing. Stockpile, Swallow and Spit Up come as a package and are more of a curiosity than a plan.

Evolution has no trick to it: reach level 38, with no item, no time-of-day requirement and no conditions. That is late, and until then you have to carry those defenses.

The habitat assigned to it by the game is urban, which fits the sewers and rubbish dumps in its entries. Its catch rate, 190 out of 255, is among the comfortable ones: there is no need to weaken it much. A wild specimen may be holding a Nugget or Black Sludge, and the latter is worth more than it looks, because that item gradually restores the HP of Poison-type Pokémon.