Crawdad

Crawdads are enemies found Underground. They act like slightly faster Crabs, walking along the ground and jumping at the player when in close enough proximity. They are also capable of moving through water unhindered.

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

Trivia

 * Like their aforementioned analogs, Salamanders and Giant Shellys, Crawdads have multiple colored variants. Also like said analogs, these differently colored variants statistically identical, unlike various Zombie varieties.
 * In real life crawdads, more properly called Crayfish, are a type of small, freshwater lobster.

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