The monster in the dream is a huge piece of content created by the dreamer, who anthropomorphize the things he worries about into a creature. The monster in the dream symbolizes the dreamer's negative relationship with himself and his fear of his own feelings and desires.
If external factors are uncertain about what happens in daily life, the dreamer must often suppress his reaction for this. This is impossible in dreams, so the dreamer's mind looks for another way out to solve the problem. He dreamed that the color of the monster could often imply certain problems: the red monster represented anger, which may be uncontrollable anger, and the yellow monster represented jealousy and envy.