When escaping from Squid Baron's lair, security will be summoned. When three eyes are summoned and disappear, do the Seer Dance for another achievement.
At the end, a Drool-stained Doll will be dropped. Go to the nearby warp zone close to the surface and warp to Armor Town. (Feel free to shake down Armor Baron for cash.) Give the doll to the woman standing outside Armor Baron's room, give the Bran-Son Doll to the person to the right of the save room, and the Manly Doll to the right of the warp room to get the Scary Doll. Warp to the Sunken Ship and give the Scary Doll back to get the achievement.