What is a monster?
Understand that what is monsterous is inherently divine: it exists without regard for the limitations of human purview; it exists beyond and without what is comprehensible, even as it might also transgress into petty, mortal regards. Monstrosity can never be fully captured on page, image , or film - it is trancendental, and those depictions will only ever be projections onto the plane, like the shadows cast on Plato's wall.
To be monstrous is to defy reason, logic, and sense, to cross beyond the motivation that can be understood, and thus - and thus, do you understand me? - the monstrous exists only through the lens of you.
Your judgement, alone, creates it.
(And that, reader, is most monstrous of all.)