One-Eyed Spiders are enemies that appear in all of the Shantae games.
One-Eyed Spiders are, like their names say, spiders with only one eye. Strangely, they only have six legs instead of eight. They are completely purple in Shantae, but in Risky's Revenge their legs have a lighter tone of purple. In Half-Genie Hero's concept art, they have marks simillar to tattoos all around their bodies.
These enemies are hanging of a ceiling, and when they are threatened, they drop and spit poison bullets. Then, they go back to the ceiling. In Pirate's Curse, they have 3 HP.