Transcend physical and moral boundaries

In biology, the word monster may be used to describe an organism that is grossly abnormal or deformed. Similarly, when used in other contexts, we find that 'monstrous' entities also tend to be somehow 'beyond the norm' in appearance or behaviour, crossing the boundaries of acceptability, manifesting traits alien to the natural order or outside of 'normal' consensus reality . Existing outside of the confinement of normative categories can provide room to breathe, and gender transgression can be emancipatory in the release from static roles.

Discussing the metaphoric role of monsters with regard to gender, Rosi Braidotti writes: "[Monsters] represent the in-between, the mixed, the ambivalent as implied in the ancient Greek root of the word "monsters", teras, which means both horrible and wonderful..." Braidotti argues that "the female body shares with the monster the privilege of bringing out a unique blend of fascination and horror."19 The female bodybuilder, in her alleged blurring of gender boundaries, inspires both awe and revulsion in some viewers.

Hybrid or shapeshifter

We often find monsters having hybrid form, as a result of mixing species, sexes, or other attributes. They may also have dislocated or superfluous parts. Thus we have the Centaur (horse-man), the Minotaur (bull-man), Echidna (snake-woman), Pegasus (horse-bird), Sphinx (woman-lion-bird), Siren (bird-woman), the griffin (lion-eagle), mermaid (woman-fish) and mandrake (plant-man).

We may also find that mythological monsters exist by virtue of some kind of transformation. In many traditions, for instance, the dragon has the power to change it's form at will. The notion of unpredictablity is also widely associated with dragons. Clearly monsters are chaos beasts, lurking beyond the cracks in the world of order. They may predate the creation of the world as we know it, living in dangerous and inaccessible places but still able to remind us of their presence in dreams and nightmares. In short, a monster is out of place, conforming to no class or violating existing classes.

Eternal and ominous 

Dracula lived for centuries. He was notoriously hard to kill, reappearing time after time when people had thought him dead until the doughty Van Helsing plunged a wooden stake through the vampire's heart.  Grendel was both ancient dragon and scapegoat, being also extremely difficult for a man to destroy.

'this unhappy being
had lived long in the land of monsters
since the creator cast them out
as kindred of Cain. For that killing of Abel
the eternal Lord took vengeance.' [4]

The Green Man of Gawain and the Green Knight could survive decapitation. Long-livedness almost to the point of indestructibility seems therefore to be common among monsters, and perhaps this is significant insofar it illustrates the extent to which our own inner demons too are extraordinarily tenacious. From a psychological perspective our instinctive drives tend also to be very deep-rooted, and very ancient in that many of these drives have been passed on from generation to generation since the dawn of human history.

Moreover,  the monster is protean, changing from period to period as society's basic fears clothe themselves in fashionable or immediately accessible garments." 

Following Jung "archetypal analysis, we may assert that while “civilization progresses to higher stages of consciousness, newer interpretations of those age-old [horror] myths become necessary so that the links with humankind's archaic past can be appropriately maintained." Iaccino thinks it "quite appropriate to refer to the new archetypes as techno-myths, reflecting the technological advances that our society has attained" ; our "cultural relevance" condition, in contrast, encompasses not merely the technological, but also the political, racial, religious, and sexual dimensions of society. And here, what gets reflected is often anything but an "advance."