If I'd thought of this sooner I would have tried to sell it. Next year, if people like it.
Obviously, the dude in the mask is a beak doctor, here in theory to treat the citizens of plague-infested towns in the Middle Ages, but in reality mostly scaring the bejesus out of them and not helping because no one had any idea how the plague worked, much less how to treat it. The prevailing theory was that it was caused by bad air. The beak is in fact stuffed with various aromatic substances, like garlic or camphor or a sponge soaked in vinegar. The idea that stinky stuff protects you from infection is a widespread and persistent one: it's not a coincidence that plague and vampires both hate garlic. Smearing oneself with excrement was a popular treatment at the time, and you can imagine how well that worked.
In fairness, the beak doctor costume probably did afford some protection from plague to the wearer, because no exposed skin means nowhere for fleas to latch on -- and while the miasma theory of disease was wrong, plague can become airborne: if an infected person coughs on you, the result can be pneumonic plague, which is even deadlier than the regular kind. (The worst and rarest kind of plague is septicemic, of which the first symptom is often death. If you're unlucky enough to get it today, when we know what germs are and have drugs, it's good night Irene if you don't manage to get those drugs within twenty-four hours, and might still be good night Irene if you do.)
I have to admit that I think the way plague spreads is kind of weirdly elegant (but skip the rest of this paragraph if you're not into that kind of thing). Plague (Yersinia pestis) gets into a flea (often Xenopsylla cheopis), where it multiplies until the flea is so gorged with it that it can't get any blood into its body. This turns the flea into a tiny plague hypodermic that is actually regurgitating plague bacilli into its host (typically Rattus rattus) as it tries to force blood into its own body. Now the rat has plague, and all the other fleas on the rat get a bellyful too. When the rat drops dead all these fleas jump off, and they're already freaking out because they're starving because they're glutted with plague, and will often latch on to the first mammal they come across even if it isn't their preferred species. And just like that, you've got an epidemic.
[DESCRIPTION OF PLAGUE TRANSMISSION PROCESS ENDS HERE]
And if you're in Europe in the Middle Ages, just like that, you've got beak doctors. One of the reference images I used for this stix comes to us courtesy of seventeenth-century Bavarian Paul Fürst:
Know who that is? It's Doktor Schnabel von Rom -- Doctor Beak of Rome! DOCTOR BEAK OF ROME. So of course now I can't get that Miami Sound Machine song out of my head. Emergency, paging Doctor Beak!
Which, uh, brings us back to Valentine's Day, I guess.