Hats in fiction, apart from looking cool, serve a variety of functions. They can be weaponized, grant special abilities, or, in the case of this trope, protect the wearer from things they really shouldn't. While protective headgear of course exists in reality in the form of helmets and visors, in fiction these items work to protect people from far more than their real-life counterparts.
This is not merely a helmet protecting a character from a head wound, but protecting them in such a manner as would be impossible in real life, whether that be because the helmet is portrayed as far stronger than it is in reality or the inciting incident as far weaker.
This is a common way to handwave a character's survival in extreme situations and excuse them being Made of Iron or having a Hard Head in the audience's eyes.
Examples:
- In Witches Abroad, Nanny Ogg has a farmhouse land on her head, but is protected by her extremely sturdy hat. Hats that stop farmhouses becomes a running joke, reappearing in later books.
- One strip of The Far Side had a construction worker standing with a toppled building resting on his helmet, with the foreman mentioning that that's why they wear hard-hats.
- Knights of the Dinner Table: A throwaway gag in a filler strip has Newt claiming his character is crouching real low and taking cover behind his "Kevlar watch cap".
- In Fallout 4 some hats can be upgraded with ballistic weave, giving them protection that actually outclasses any non Power Armor helmet.
- Kerbal Space Program: Kerbonaut helmets are apparently hard enough to survive impacts that would otherwise kill the wearer.
- Rabbids Go Home features enemies with large yellow soundproofed helmets that protect them from the standard attack. They have to be rammed with a boost instead.
