If you want to understand how 'madness' in (cosmic) horror doesn't need to be tied to mental illness in your #DnD/other #RPG game, look no further than videos of anti-maskers being told to leave a store.

People are screaming, hurling themselves at things, throwing objects, and straight-up pissing on the floor because someone told them "no" in a no-stakes situation, how the fuck do you think they'll react if they see a squid from Pluto who exists at a 90 degree angle from reality

The opening section of this adventure I'm writing based on The Thing, an NPC does something very shocking. Something that is, by any casual observer, not sane. I stress in a DM note that this character is not 'crazy,' but terrified beyond their capacity to cope rationally.

Horror is stronger when you emphasize that completely normal people are capable of 'madness' when faced with the overwhelming, the alien, the eldritch, and the terrifying.