In Chapter 10 of Percy Jackson's The Lightning Thief, what is the Mist?
When Chiron gives Percy the gift from his father, Poseidon, a magical sword named Riptide, Percy worries that mortals will see him wielding a giant sword and freak out. However, Chiron assures him that Mist is very powerful, and this Mist will generally prevent mortals from seeing the truth about things and events having to do with gods or divine objects. Chiron says that it is "'Remarkable, really, the lengths to which humans will go to fit things into their version of reality.'" What he seems to mean by this is that human beings need the world to work the way we already conceive it to, and since we don't believe that someone can uncap a pen and suddenly be holding a huge sword, we simply won't be able to see that this is the reality. Therefore, our minds simply replace things that we don't think could be real with things that we believe can be; for example, instead of seeing Percy holding Riptide, we might see him holding a baseball bat because this fits with our ideas about reality.