I think he’s a monster, in the classical sense, that is.

The Latin monstrum, had a broader meaning, encompassing any kind of warning from he gods (demonstrate has the same root). Rulers then, just as now, weren’t very observant of subtle hints, so back then this often took the form of godzilla wrecking shit.

Take the story of Laomedon, the Trojan king. After having some very nice city walls built for him, he neglected the small matter of actually paying his workers. Unfortunately for him said workers happened to be gods, who have slightly more bargaining power than your average worker, with the eventual industrial action including a cetus, a kind of sea monster, sent by Poseidon.

Rather annoyed at having his shit wrecked by a sea monster, Laomedon enlisted Heracles to kill it. Which, of course, being a hero, Heracles did very heroically. Now Laomedon, being a complete fucking moron, failed to learn absolutely anything from this, and decided it was a good idea stiff Heracles out of payment for this task.

In response, Heracles raised an army, besieged Troy, and killed Laomedon and his sons. This bought the matter to a close.