O

O is the next slime elemental, 1000 years later. O can be seen taking cover after X shoots at him in the, "Come Along With Me" intro.

Appearance
O is basically a chubby, slime humanoid who has a slime "O" surrounding their face. Tiny green specs can be seen inside of O's body.

Trivia

 * Steve Wolfhard included O to give closure on Slime Princess.