Character: monster kid
Monster Kid is a young monster who will stop at nothing to see their idol Undyne in action.
Monster Kid is a yellow monster with no arms, a tail, and spines on the back of their head. They have markings under their eyes, presumed to be black eyes from them falling so often. One of the markings is bigger than the other. They wear a yellow shirt with brown stripes.
This tag implicates undertale_(series) (learn more).