The Sugar Cube is a Candy Person. He has not spoken yet, but he can be seen in many crowds. If the viewer looks closely when Ice Queen (disguised as Prince Gumball) is walking towards Fionna during the Biennial Gumball Ball, a gender-swapped version of Sugar Cube can be seen. He seems to have a girlfriend because he is seen kissing in "Go With Me." He also takes off part of his head to make Princess Bubblegum old again in "Too Young."
Sugar Cube has three seen faces (one on the front, one on the left side, and one on the right side) and wears a cowboy hat and shoes. His body is a typical sugar cube, and he also has sparkles on each side.
- Sugar Cube's girlfriend is a Purple Candy Guava.