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. 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. 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 elationship 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. You might like to consult the entries for Colour, Dinosaurs, Fabulous Beasts, Minotaur and also the Introduction for the Hero's Journey.