Humans have invented ways to transport themselves quickly across vast distances and over otherwise impassable geographical barriers such as mountains, oceans, canyons, and rivers. But it’s not just humans on the move.
Networks of roads and highways have become major pathways for the introduction and spread of non-native invasive species at a rate thousands of times faster than would naturally occur.
Yes, monsters do exist, and in the environmental realm they take the form of invasive species.
These monsters are largely a product of human interference in an ecosystem — whether by introducing a non-native species accidentally or on purpose, or by altering habitat in such a way that a native species becomes invasive and disturbs the natural ecosystem balance. Invasive species that do not evolve in an ecosystem over time often undergo population “release” with the possibility for unlimited and uncontrollable breeding potential.