Dreaming about monsters and demons is very common. They may represent negative forces inside of yourself and in your life. Most of the monsters are representing your own negative characteristics and tendencies.
The monster in your dreams could be your fear, bad temper, negativity, smoking habit, or anything else that is hurtful and needs to be changed.
The way that you deal with the monster in your dream is generally symbolic of the way you are dealing with the corresponding negativity in your daily life.
If you wake up from this dream and are very frightened, just remember that your mind created those images and that their purpose is to teach you something about yourself.... The Bedside Dream Dictionary
Our own internal emotions or drives we are frightened of. Use the approaches in dream processing to change the monster into usable personal resources; dread of death; a monstrous deed done or lie lived; our negative relationship with the power which moves us to growing, mating and dying. ... A Guide to Dreams and Sleep Experiences
1- Any monster appearing in a dream is something that we have made larger than life. We have personalised it so that whatever is worrying us appears as a creature. It usually stands for our negative relationship with ourselves and fear of our own emotions and drives.
2- When, in everyday life, events get out of proportion we often have to suppress our reactions. In dreams we cannot do this and so our minds create some way of dealing with the problem. Often the colour of the monster (see Colour) will give us some indication of what the problem is, thus a red monster would indicate anger (possibly uncontrolled), whereas a yellow one might suggest resentment.
3- Fear of death and all that goes with it.
A monster can highlight a more childlike fear, and can be looked at thus.... Ten Thousand Dream Dictionary
To see a monster or monstrous fish in the sea, is not good; but out of the sea every fish and great monster is good, because then they can hurt no more, or save themselves. And therefore, besides that our dream signifies that our enemies cannot hurt us, it saith moreover that the wicked shall be punished.... The Complete Dream Book
Depth Psychology: Monsters appearing in a dream reflect a fear of dying or hate directed toward oneself. Unresolved events or emotional experiences hiding beneath the surface have too much influence over you. Failing to learn how to control these energies may lead to serious problems. Seek professional help if monsters appear in your dreams frequently. See Demons, Mysterious Creatures.... Dreamers Dictionary
A monster is usually large and, therefore, can highlight a childlike fear – perhaps the fear of death and all that goes with it – or the fear of failure. Such an image tends to be encountered at some point in the hero’s journey.... Dream Meanings of Versatile
Psychological / emotional perspective: When, in everyday life, events get out of proportion we often have to suppress our reactions. In dreams we cannot do this and so our minds create some way of dealing with the problem. Often the colour of the monster will give us some indication of what the problem is; a red monster would indicate anger (possibly uncontrolled), whereas a yellow one might suggest resentment.... Dream Meanings of Versatile
Material aspects: Any monster appearing in a dream represents something that we have made larger than life. We have personalized it so that whatever is worrying us appears as a creature. It usually indicates our negative relationship with ourselves and fear of our own emotions and drives.
If we vanquish the monster, it is said that we must take care not to kill it, since we may be killing off part of our personality. Equally it should not be allowed to overcome us; self-survival kicks in and we will normally wake up before it does.... Dream Meanings of Versatile
Dreams about monsters come from repressed emotions.
The monster may represent a side of your personality that makes you uncomfortable. This dream often means that you would do well to consider a change of direction, or give up a bad habit that’s unhealthy for you.... My Dream Interpretation
Beast. Your animal nature is becoming too strong, too frightening, meaning that you are afraid of your own strength and drives. It could also indicate a person (Father or Mother) who appears overly powerful.
Talk to the frightening monster in your dream, have it out with him and observe him.
Mythical creatures, like dragons and ocean monsters, point to moral conflicts that may cause personality disturbances. Seek therapeutic help when these images appear often and include a great amount of fear.... Little Giant Encyclopedia
To dream about a sea monster suggests that issues from your unconscious are struggling to come to the surface. You may need to see yourself more clearly, and face the unpleasant aspects of yourself, in order to become the person you want to be.
If you killed the monster in your dream, you will successfully deal with your personal issues and rise above them.... My Dream Interpretation