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Official artwork of Gastrodon

#0423

Gastrodon

Gen IV

Sea Slug Pokémon

WaterGround

Pokédex entry · Diamond

It has a pliable body without any bones. If any part of its body is torn off, it grows right back.

Height
0.9 m
Weight
29.9 kg
Base EXP
166
Growth
Medium
Catch rate

75/255Medium

Friendship

70/255

Base stats

HP111Attack83Defense68Speed39Sp. Def82Sp. Atk92
HP★
111
Attack
83
Defense
68
Speed
39
Sp. Def
82
Sp. Atk
92

Total 475

High

EV yield +2 HP

Real ranges (IV 0–31 · EV 0–252 · nature included)

MinMax
HP171218
Attack79148
Defense65132
Speed39100
Sp. Def78147
Sp. Atk87158
Total519903

About Gastrodon

The Sea Slug Pokémon has the soft body of a sea slug and moves close to the coast, where it feeds on invisible plankton. Its appearance is deceptively fragile: its slimy coating cushions blows, and its regenerative ability lets it regrow parts nibbled by fish Pokémon within a few hours. When a natural enemy threatens it, it secretes a purple fluid and runs away; it does not need to fight to escape unharmed.

Pokédex entries also preserve traces of an earlier stage: it once had a large protective shell and still retains a thin, hard plate beneath the skin on its back. Its shape and colour depend on its surroundings and diet, which fits with its life in shallow waters and calm-surf beaches.

It is the second stage in its evolutionary line. Shellos evolves into Gastrodon upon reaching level 30, and the change reinforces its marine mollusc-like appearance without abandoning its connection to the coast or the sliminess of its body.

Combat analysis

×4

Double weakness

Grass
×½

Resistance

FirePoisonRockSteel
×0

Immunity

Electric

Gastrodon in depth

A slug with traces of a mollusc

The design is based on a sea slug, particularly animals capable of expelling a purple secretion to defend themselves. The rounded shape, the mantle covering the upper part and the protuberances on its back bring traits from real molluscs into the design without turning it into a literal copy. The ancient shell mentioned in several entries adds a fossil explanation for its current silhouette: the shell disappeared, but a tough plate remained on its back.

The English name Gastrodon combines the idea of a gastropod with the suffix “-don”, which is common in scientific names and associated with the Greek word for “tooth”. The Japanese トリトドン is romanized as Tritodon and retains the “-don” ending, along with a reference to Triton or certain marine molluscs. It also fits the image of a heavy-looking marine creature, almost bull-like because of the shapes of its appendages.

From Sinnoh to Paldea

Gastrodon debuted in the fourth generation alongside Shellos. Since then, Pokédex entries have returned to four ideas: the purple secretion, regeneration, a diet based on plankton and the loss of its shell. Later generations added details about its physical toughness, its trail of slime and its occasional presence on dry land.

Storm Drain’s function also changed. In its first appearances, it drew in Water-type moves; later, it began to nullify them and raise Special Attack. That adjustment turned a situational Ability into the foundation of its current defensive use. Its silhouette also received visual changes before the sixth generation, although the sea-slug concept remained intact.

What it brings compared with other Water and Ground types

It shares its typing combination with species such as Swampert, Quagsire and Seismitoad, but it does not fill exactly the same role. Swampert usually applies more pressure on the physical side, while Gastrodon concentrates its value in its HP, recovery and ability to switch into Water thanks to Storm Drain. Quagsire competes from another angle when its Ability ignores stat changes, and Seismitoad offers a different profile of Speed and moves.

Gastrodon’s spread favours long games: 111 HP, 82 Special Defense and access to Recover. Its Defense of 68 means its switches against physical attackers have to be measured carefully, and its 39 Speed points mean it acts late almost every time. It should not be used as the main attacker; it works better by switching into a move it resists or nullifies, recovering and punishing the switch with Muddy Water, Earth Power or Spikes.

How to use it without giving away free turns

The first rule is to keep it away from Grass-type moves. Storm Drain lets it take advantage of Water attacks aimed at it or an ally, but it does not protect it from Grass coverage thrown out by the same opponent. When the enemy relies on Electric or Water, Gastrodon can halt the momentum and force a switch. That turn can be used to Recover, set Spikes or attack with Earth Power.

It is not a good idea to leave it in against opponents that can poison it or boost their stats without fear. Its low Attack and reduced Speed make it lose the initiative easily, and strong physical hits wear it down before it can take advantage of its HP reserve. Sand Force offers an offensive route during sandstorms, but Storm Drain remains the Ability that defines most of its defensive uses.

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