Pearl pygmy skulls are large, crystalline rocks shaped like geodesic, cycloptic skulls that appear in "Fionna and Cake." They are light pink-colored with many sharp teeth. The Ice Queen (disguised as Prince Gumball) picked up one in Marshmallowy Mweadows that she said reminded her of how Fionna's eyes sparkle.
- It is possible that Pearl Pygmy Skulls are made of Rock Candy as they're found in the Candy Kingdom in Ice King's fanfiction (it is also unknown if they even exist).
- Ice Queen (disguised as Prince Gumball) was originally supposed to find the one she gave Fionna in an iron maiden device.