Robot Hat

The Robot Hat is a vanity item equipped on the Social Helmet Slot. It is a 1/500 drop from Piranhas.

Trivia

 * This hat appears to be a reference to the hat worn by the protagonist from the popular indie game Cave Story, as seen here. While the Terraria sprite does resemble the Cave Story sprite, the resemblance is more apparent in official Cave Story artwork, and depictions in the credits of Cave Story.