Cloyster is actually a black pearl within two shells. The first shell is purple and rugged, while the second shell is gray. When the second shell is opened, a spike is revealed. Its face has a cruel look upon it.
Cloyster can have the ability Shell Armor or the ability Skill Link. Shell Armor prevents any critical hits to be landed on Cloyster. Skill Link increases the frequency of multi-hitting attacks. Cloyster's shell is extremely solid. It fights by keeping its shell tightly shut for protection, and by shooting spikes to repel foes.