WPA quack poster
The pattern
This still is filed under Public health warning.
Define
A warning designed to change a health behavior (stop, screen, stay home), not to sell a brand.
Mechanism
Fear with a next step. The threat is specific. The action is doable today. Fear without an action is cruelty.
Verdict
The risk is real and the action is clear. Official or civic voices help.
Why it works
The warning is not an argument, it is a checklist. Three concrete, observable behaviours - promising a cure, demanding advance payment, advertising - convert an unanswerable medical question the reader cannot judge into a social test the reader can apply in five seconds. The drawing carries the emotional half. Reducing the fraud to flat geometry with a single blank white eye makes him unreadable rather than villainous, which is precisely the fear being sold: you will not be able to tell. Routing the speech line from his mouth into the copy circle makes the warning read as his own exposed pitch, so the reader catches him rather than being lectured at. The word NOT is set larger than the lines around it because the whole sentence inverts on it; miss that word and the poster says the opposite.
Steal this when
Use this when your audience cannot evaluate your category on the merits and is therefore vulnerable to whoever sounds most confident. Give them two or three observable red flags they can check without expertise, and let one stark image carry the menace so the copy can stay procedural.