Tentacruel

The official category promises a Jellyfish Pokémon and undersells it. Beneath the translucent bell is a dark body with a beak, visible eyes and eighty tentacles which, according to Pokédex entries, move independently of one another. That number is the basis of almost everything written about the species: the tentacles lengthen or shorten at will, spread out like a net to catch prey and immobilise it with a highly toxic substance that causes sharp, intense pain. It can hold up to eighty prey at once. It loses limbs as it ages.

The other feature is the red orbs on its head. They shine just before it unleashes an ultrasonic blast at everything around it, and the burst raises tremendous waves. One entry goes further and describes the effect on the entire sea: when several gather in large schools, the surrounding fish Pokémon disappear without a trace.

It is 1.6 m tall and weighs 55 kg. It completes a two-stage line — Tentacool evolves at level 30 and that's where the road ends, with no third form or regional variants. It lives in the sea. Wild specimens may be holding a Poison Barb.

The 515 points are distributed very unevenly, and that's the whole appeal. Special Defense 120 and Speed 100 at the top; HP 80 and Special Attack 80 in the middle; Defense 65 and Attack 70 dragging behind. It's a fast special wall whose jaw gets broken by any decent physical hit.

The Water and Poison combination defends well: it resists Fire, Water, Ice, Steel, Fighting, Poison, Bug and Fairy, and is only weak to Electric, Ground and Psychic. It performs much worse offensively, because Poison only hits Grass and Fairy for super effective damage, and its Special Attack of 80 doesn't make Sludge Bomb or Hydro Pump particularly threatening without investment.

What keeps it afloat is a rules detail: as a Poison-type that is grounded, it absorbs Toxic Spikes on its own side of the field as soon as it switches in. It also learns Rapid Spin as an egg move, so it clears hazards and Spikes from the other side as well. In Smogon, it has been a fixture in UU for years doing exactly that, with its own Toxic Spikes from TM, Sludge Bomb, Ice Beam and Hydro Pump, while checking opponents such as Keldeo and Primarina.

Of its three abilities, Liquid Ooze is the one that changes games: anyone draining its HP takes damage instead of healing. Clear Body blocks stat drops, while Rain Dish, its hidden ability, restores HP in rain. The problem is recovery: without rain, it relies on Rest or the inherited Aqua Ring, and wears itself down through repeated switches.

It belongs to a single Egg Group, Water 3, the one for arthropods and marine molluscs, which narrows the list of compatible partners considerably. The sex ratio is exact: 50% female.

Twenty incubation cycles equal roughly 5355 steps, an average figure within the first generation. Several moves come from the egg that it cannot get by levelling up or by TM, and one of them is what gives it a job in battle: Rapid Spin. It also inherits Mirror Coat, Aqua Ring, Aurora Beam, Acupressure and Tickle.

The evolution is straightforward. Tentacool reaches level 30 and that's it — no items, no time requirements, no friendship involved. What does matter is the experience curve, Slow, the most expensive of the usual four, so that level 30 arrives later than expected if it comes from breeding species with a medium growth rate.

Its habitat is the sea and its catch rate is 60. It's in the awkward middle of the scale: not a 255 that drops to the first Poké Ball, but not the 45 of starters or pseudo-legendary Pokémon either. Weakening and poisoning it first is usually enough. Defeating it awards 2 Special Defense EVs and 180 base experience.