Yellow Face appears to be a poorly drawn, scribbled yellow smiley face or head. His facial details and outline are black, and his "body" is bright yellow. When talking, his mouth opens and closes on a poorly made and repetitive loop, contrary to most other contestants. When he yells or talks loud, he also grows big and usually vibrates quickly and rapidly.
In "Gardening Zero", he is revealed to have a skeleton, which also has a nose not seen in the alive form.