That was Clem Sypher's Dragon--Jebusa Jones's Cuticle Remedy.

He drew so vivid a picture of its foul iniquity that Zora was convinced that the earth had never harbored so scaly a horror.

Of all Powers of Evil in the universe it was the most devastating.
She was swept up by his eloquence to his point of view, and saw things with his eyes.

When she came to examine the poor dragon in the cool light of her own reason it appeared at the worst to be but a pushful patent medicine of an inferior order which, on account of its cheapness and the superior American skill in distributing it, was threatening to drive Sypher's Cure off the market.
"I'll strangle it as Hercules strangled the dog-headed thing," cried Sypher.
He meant the Hydra, which wasn't dog-headed and which Hercules didn't strangle.

But a man can be at once unmythological and sincere.