Giant Shelly

A Giant Shelly is an Enemy found in the Cavern layer. They attack by curling into their shells and hurling themselves at players, though they will stall in midair and drop to the ground if they are damaged during their flight. Giant Shellies attack very quickly and deal high damage for the stage in the game where they are found.

Giant Shellies are unique in that their ability to spawn is connected to two other enemies: the Crawdad and the Salamander. Of these three enemies, a world will choose two types that it can spawn, leaving the third inaccessible. Giant Shellies will never spawn in a world that features both Crawdads and Salamanders together.

Trivia

 * Like their aforementioned analogs, Crawdads and Salamanders, Giant Shellies have multiple colored variants. Also like said analogs, these differently colored variants are statistically identical, unlike various Zombie varieties.
 * The Giant Shelly's name may be a reference to Scott Lloyd Shelly, who composed much of Terraria's soundtrack.

History
Coquillage Géant 큰 조가비