What is the evolution line for Cloyster?

Cloyster evolves from Shellder when exposed to a Water Stone. Shellder is its basic form, and Cloyster is its Stage 1 evolution.

What are the energy costs for Cloyster's attacks?

Clamp Crush costs one Water Energy and one Colorless Energy, while Spike Cannon costs two Water Energy and one Colorless Energy.

What is Cloyster's weakness on this card?

Cloyster has a weakness to Grass-type Pokémon, indicated by a x2 multiplier for damage from Grass attacks.

Who illustrated this Cloyster card?

This Cloyster card was illustrated by Masakazu Fukuda, whose signature is visible at the bottom of the card.

Is this Cloyster card considered rare?

This particular Cloyster card from the Generations set is a common rarity, so it is not considered rare in terms of its print run.

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CloysterGenerations #20 Pokémon Card

Generations·#20

Cloyster, the formidable Bivalve Pokémon, is a Water-type creature from Generation I, known for its incredibly hard shell and its evolution from Shellder. This specific card, #20 from the 2016 Generations set, is a common rarity that stands out due to its celebratory nature as part of the Pokémon franchise's 20th anniversary. Here, visitors will find comprehensive details on its Pokédex lore, its attacks with their energy costs and effects, along with its weakness, resistance, and retreat cost, providing a full overview of its mechanics and background.

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Card Number: #20
Release Date: February 21, 2016
Language: EN
Set Code: TwentiethAnn

Cloyster, the Bivalve Pokémon, is a Water-type Pokémon introduced in Generation I. It evolves from Shellder when exposed to a Water Stone, showcasing a dramatic transformation from a small, bivalve mollusk to a formidable, spiky shell creature. Cloyster's natural habitat is deep, cold ocean waters, where it remains largely motionless, awaiting prey. Its diet primarily consists of small fish and other marine organisms, which it captures by opening its shell and ensnaring them with its internal body. Cloyster is renowned for its incredibly hard shell, said to be tougher than diamonds, which protects its vulnerable core. In the games and anime, Cloyster is often depicted as a powerful defensive Pokémon, capable of enduring significant damage while striking back with icy attacks. Its iconic design and intimidating presence have made it a memorable figure in the Pokémon franchise, representing the resilience and hidden dangers of the ocean depths. Its role often involves being a sturdy wall in battles, leveraging its high defensive stats to outlast opponents.

Last updated: April 11, 2026